Sony A33 Review

Overview

Sony Alpha SLT-A33 Overview

Reviewed by Dave Etchells, Mike Tomkins, Shawn Barnett, and Zig Weidelich
Preview Posted: 08/24/2010
Updated to Full Review: 10/29/2010

Just three months after launching the NEX-3 and NEX-5 single-lens direct-view (SLD) cameras, Sony offers up yet another interchangeable lens alternative to the traditional DSLR, with the Alpha SLT-A33, and its closely-related sibling the SLT-A55. Instead of being mirrorless, the new digital cameras employ a "translucent mirror," more commonly known as a pellicle mirror. This advanced translucent mirror remains fixed in place during operation, allowing most of the light to reach the imaging sensor, while a small percentage is reflected to a dedicated autofocus sensor.

It's what this high technology allows that's so exciting: real-time, phase-detect autofocus while firing off up to seven 14-megapixel frames per second in the A33, and ten 16-megapixel images per second in the A55. Few other large-sensor cameras offer frame rates this fast. DSLRs rivalling the A33's speed are available for a little over $1,500, while only professional cameras that cost around $5,000 can match the speed of the A55 -- and they're still not capable of real-time autofocus between shots like the new Sony Alpha SLT cameras. Real-time phase-detect autofocus is also constantly available in Movie mode, something no current SLR can achieve.

While the translucent mirror design isn't quite as space-efficient as the mirrorless design of an SLD camera, it's still smaller than that of a traditional SLR, most of which need to provide room for the mirror to swing upward before image capture can commence. That translates to an uncommonly compact body by SLR standards, although it's still a bit larger than an SLD, especially in terms of body thickness. Unlike SLD cameras, though, the Sony SLT cameras all accept the entire line of standard Alpha-mount lenses, a significant advantage if you already own a large collection of Alpha-mount glass.

Since the translucent mirror only reflects enough light to provide for the autofocus sensor, not an optical viewfinder as most pellicle designs permit, Sony has adopted full-time live view in the Alpha A33 and A55. In place of the optical viewfinder from a traditional SLR, the SLT cameras have an electronic viewfinder with 1,152,000 dot resolution. The EVF LCD is time-multiplexed -- that is to say, it shows each color in sequence at every pixel location, rather than the separate, adjacent color dots of most electronic viewfinders. This makes it harder to distinguish individual pixels. The Sony SLT-series cameras also sport a wide-aspect 3-inch LCD with 921,600-dot resolution. Taking full advantage of the camera's full-time live view shooting, the super-slim LCD tilts 180 degrees vertically, and swivels 270 degrees for easy viewing from most any angle. The cameras also include TruBlack technology borrowed from Sony's picture frames.

Several hot features were brought over from Sony's NEX and Cyber-shot digital cameras, including Sweep Panorama, 3D Sweep Panorama, Auto High-Dynamic Range, and Handheld Twilight modes, each of which strategically combine and align several images into one seamless shot. It's pretty impressive stuff. As if that weren't enough, Sony has added an extra mode for the SLT-series cameras -- Multi-Frame NR -- which operates similarly to the handheld twilight mode, but allows the ISO sensitivity to be specified.

The Sony Alpha A33 lacks one feature found in the A55V (the only version of the A55 that's sold in the US market) -- a built-in GPS receiver. It's still possible to geotag images and movies from the A33, but doing so will rely on an external GPS logging device and PC software that can backtrack to calculate the location at which images and movies were shot -- not nearly as seamless a solution as the A55V's ability to geotag images and movies straight out of the box.

The Sony Alpha A33 accepts both Memory Stick Pro Duo / Pro-HG Duo, and SD / SDHC / SDXC media, and is powered by an InfoLithium battery pack.

The Sony A33 ships in the US market from mid-October 2010, with pricing of US$750 for the camera body and an 18-55mm kit lens, or $650 for the body only package.

Sony Alpha A33 User Report

by Dave Etchells, Mike Tomkins, and Shawn Barnett

Rather than rest after establishing products in every major sector of the interchangeable lens digital camera market -- APS-C SLR, full-frame SLR, and most recently single-lens direct view -- Sony is boldly striking out to create yet another category with the launch of its very first translucent mirror cameras. The main goal of the new design: achieving unprecedented autofocus and capture speed from an APS-C sensor, interchangeable-lens, consumer digital camera. Comprising a new SLT series, the Sony Alpha SLT-A33, A55, and A55V are closely related cameras sharing the same basic design, with only a few internal features as major differences.

Look and feel. Although it lacks the reflex mirror of an SLR, having replaced it with a fixed translucent mirror, the basic shape of the Sony SLT-A33 still follows that of a traditional SLR fairly closely. That's because, since it accepts the same Alpha lenses as Sony's DSLRs, the Sony A33 also has to accommodate the same backfocus distance, which is one of the main contributors to the size -- and especially, the depth -- of an SLR camera. Removing the reflex mirror still provides potential for space and weight savings, and Sony has taken good advantage of this. Most obviously, the drive mechanism that raises and lowers the reflex mirror in a traditional SLR isn't needed. The translucent mirror design also provides other opportunities to optimize component placement. As one example of this, Sony has increased the angle of the translucent mirror, so that instead of directing light directly upward at a 90 degree angle as it would for a viewfinder prism, it is actually angled upward and slightly forward, allowing the autofocus sensor to be moved forward, providing more room for the electronic viewfinder assembly directly to the rear.

The net result is that, while the Sony Alpha A33 is a fair bit thicker front-to-back than single-lens direct-view (SLD) cameras, which can do away with the bulky mirror box entirely, it's still an exceptionally small camera by SLR standards. If the handgrip depth is ignored, the Sony A33 is actually just a little smaller than the smallest digital SLR to date, the Olympus E-420. Unlike the smallest SLD cameras, the A33 still includes a built-in electronic viewfinder -- and for those SLDs that can accept an optional electronic viewfinder, much of their size advantage over Sony's SLT-series models is erased once it's installed. Sony's A33 thus occupies a comfortable middle ground, sacrificing little of the versatility of a traditional SLR, yet bringing a worthwhile advantage in portability.

While not quite as light as the Olympus E-420, which lacks an in-body image stabilization mechanism, the Sony Alpha SLT-A33 is certainly in the same ballpark. The A33 weighs 17.3 ounces (1.08 pounds, 492g), with battery and flash card (but no lens), while the Olympus E-420 weighs 15.7 ounces (0.98 pounds, 445g) loaded but without a lens. The lightest SLD, Sony's NEX-5, weighs just 17.7 ounces (1.1 pounds, 502g) loaded and with its kit lens attached -- just 0.4 ounces more than the A33 body without a lens.

Thanks to its smaller body, and especially their reduced height due to the lack of a pentaprism or pentamirror assembly, the Sony A33 looks rather aggressive, with the popup flash housing hunched low over the top of the lens barrel. A soft, rubber pad surrounds most of the handgrip, and wraps around to the rear of the camera to cover a small, contoured thumb grip area as well.

Due to its diminutive stature, most photographers will find that the grip only accommodates two fingers, with the index finger resting on the shutter release button above, and the little finger curling beneath the bottom of the camera. This might seem a little crowded, but with the light, plastic-bodied 18-55mm kit lens, handling is nonetheless good, with the combination feeling extremely well balanced. Using larger, heavier lenses, the grip size is too tiring for single-handed shooting, so the photographer's left hand will need to serve double duty, adjusting zoom or focus while simultaneously taking up the weight of the lens itself.

Centered to the right of the lens in the photo above is the lens release button, while the depth-of-field preview button is positioned snugly at the bottom left corner of the lens mount. A small plastic panel in the handgrip conceals the infrared remote control sensor at top, and the self-timer lamp beneath. Directly beneath the shutter button and power switch is the control dial, used to make adjustments to exposure and variables and menu options.

From the top of the Sony Alpha A33 camera body, you can just see the stereo microphones, located on either side of the flash hot shoe on the sides of the viewfinder / popup flash housing, as well as the three hole grille the speaker (above the Finder/LCD button). At the top of the handgrip is the popular combination of a shutter button surrounded by a power switch, making it easy to quickly power on the camera and snap a picture with one finger. The Finder / LCD button allows the A33 to be manually switched between shooting with the electronic viewfinder or the rear LCD panel. Upper right of this is a D-Range button that provides access to Dynamic Range Optimizer and High Dynamic Range shooting options.

The Mode dial on the left shoulder is used to select the camera's operating mode. An angled panel allows you to view four buttons from either the rear or above: Menu, Movie, Exposure Compensation, and Auto-exposure Lock buttons.

You can also see the top of the mechanism for the tilt / swivel LCD panel, peeking out on either side of the electronic viewfinder. The viewfinder itself projects quite a bit from the rear of the camera, a decision that was apparently necessitated by the tight packaging of components in front, including the AF module, popup flash, hot shoe, and microphones.

When using the Sony A33 with a neckstrap and particularly light lens, this might cause it to bump against your body, but with even moderately heavy lenses the camera will turn face-down even though this doesn't match the strap mount alignment, and this won't be an issue. A positive side-effect of the EVF positioning is that it makes it easier to keep your nose from smudging the LCD panel. Given the relatively tight eyepoint of the electronic viewfinder, the projection also helps prevent the photographer having to jam the camera to their face to see the entire viewfinder display.

Tilt / swivel LCD. At the rear, the 3-inch LCD dominates much of the available real-estate, and its tilt/swivel mechanism -- appearing for the first time in an Alpha camera -- can be clearly seen. The display tilts down 180 degrees and then swivels 270 degrees, allowing it to face any direction except to the front right (handgrip) quadrant. The design not only allows easy framing of high- and low-angle shots, but also allows subjects in front of the lens to see themselves -- but only when somebody's available to hold the camera. Since the display tilts downwards, it will be blocked from view when mounted on a tripod, and can't be extended beyond the 90-degree position with the camera placed on a flat surface, so the only way to use it for self-portraits is to hold the camera at arm's length. It can also be difficult to deploy and use with the camera mounted on a tripod.

On the positive side, the mechanism does allow the LCD to be folded facing inwards, providing some degree of protection against minor knocks and smudges when traveling and when you're content to use the EVF instead. The Xtra Fine LCD panel has a 921,600-dot resolution. The display also uses Sony's TruBlack technology, which couples a reinforced glass cover plate with anti-reflective film, and a resin filling that removes the air gap beneath the cover plate, which the company says improves contrast and reduces glare under harsh sunlight.

Thanks again to the relatively short stature of the Sony A33, the remainder of the rear-panel controls are rather difficult to reach when shooting single-handed, even with the relatively light kit lens attached. There are only a few buttons, Function, Playback, and Delete, plus a four-way controller with a central OK button. This isn't an issue if shooting two-handed, but you do have to change your grip fairly substantially to reach any further than the top quadrant of the four-way controller. With real-estate at a premium, Sony has only provided markings on the controller for the alternate functions offered during shooting (and in the case of the Up / Display button, during playback).

Translucent (pellicle) mirror. Undoubtedly the biggest story of the Sony SLT-series cameras is their use of a translucent mirror. Also known as pellicle mirror, this works by allowing most light to pass through to the imaging surface beneath, while a small portion is reflected for other purposes. Sony is not the first camera manufacturer to use a translucent mirror in an SLR-style camera, with the manual focus Canon Pellix film camera from 1965 taking that credit. The Pellix was followed by a handful of other pellicle mirror-based SLRs from Canon, Nikon, and Mamiya, largely designed for professional photographers, and manufactured in very limited production runs. It wasn't until 1989's Canon EOS RT that the first autofocus pellicle camera was released, followed by the EOS-1N RS in 1995. Fifteen years later, Sony has become the first company to resurrect the pellicle mirror for use in an interchangeable lens digital camera.

Full-time autofocus. There are several advantages to the use of a translucent mirror in place of a traditional single-lens reflex mirror mechanism. The Sony Alpha A33 uses the design to allow it to simultaneously provide a live view feed with full-time phase detection autofocus. Most of the light is transmitted to the image sensor, while a smaller portion is delivered to the phase detection AF sensor, where it can be used to perform focus adjustments -- even during live view, high-speed shooting, and movie recording.

Fifteen autofocus points are arrayed in an almost oval pattern.

While contrast-detection AF systems these days are much faster than they used to be, phase-detection AF generally still has the edge in terms of outright speed. It also involves less hunting around the point of focus, since phase-detection systems can determine both the focus direction and the required adjustment. On the flip side, though, contrast-detection systems generally offer more precise focusing, since the image sensor itself is responsible for confirming the point of focus, without any reliance on the lens's focus drive and AF sensor alignment being perfectly in spec.

The Sony A33 adopts a newly developed phase-detection autofocus sensor and lens module with 15 points, of which three are cross-type. AF points can be selected automatically or manually, and both predictive control (tracking) and face detection are included, although the cameras can only focus on detected faces if they fall under a phase detection point. Autofocus working range is -1 EV to +18 EV (at ISO 100 equivalent), and there's no dedicated AF assist lamp, with the A33 relying on low-power bursts of internal flash or an external strobe's assist lamp for focusing in low light.

Continuous shooting. As well as allowing full-time AF during live view and movie capture, the translucent mirror design of the Sony Alpha A33 brings another important advantage. During burst shooting with continuous autofocus, a traditional SLR has to drop its mirror between each frame, wait just long enough for any mirror vibration to settle, perform the AF measurement, and then raise the mirror again so that the next frame can be captured. Using a pellicle mirror, there's no reflex mirror to raise, and so the only delay required is to wait for the lens aperture to open after the exposure has been completed. For even swifter burst shooting, the aperture can be locked at either F3.5, or the maximum aperture of the lens, whichever is smaller, removing the delay required to set and reset the aperture to allow focusing between shots. The Sony A33 offers burst shooting at up to six frames per second ordinarily, but with the aperture locked in Continuous Priority AE shoots even faster, providing a very respectable seven frames per second. (Its sibling, the A55, is even swifter with a whopping ten frames per second in Continuous Priority AE mode.) Sony also notes that, for like framerates, the autofocus system in the Alpha A33 can be active for a greater proportion of the time compared to a traditional SLR, providing more data from which to make AF tracking predictions.

Burst depth for the Sony A33 is seven Raw or Raw+JPEG frames, and 16 Fine or 20 Standard JPEG frames in a burst. That's quite a bit less than the A55, which can capture twenty Raw or Raw+JPEG frames, while JPEG shooters can expect 35 Fine or 39 Standard-compression frames, but in our experience, the Sony A33 makes up for this deficit somewhat by clearing its buffer much faster. This means that although the A55 will get you more shots in a burst, the A33 will be ready to start another burst much sooner.

One quirk of the design of the Sony A33 (and shared by the A55) unfortunately conspires to make this high-speed burst shooting somewhat harder to use than would otherwise be the case. For both the ultra-speedy Continuous Priority AE mode, and the six frames per second Continuous Advance Hi mode, the live view isn't shown on the viewfinder or LCD panel. Instead, the A33 shows the previously captured image. This makes it harder to follow fast-moving action, since rather than seeing what's you're trying to frame, you're effectively seeing a static slideshow of what happened around a tenth of a second earlier. This problem, incidentally, is also found on all of the SLD's we've reviewed. The Continuous Advance Lo mode, which shoots at around 2.5 frames per second on the A33, does return to the live view between shots, but only briefly -- so it can still be a little hard to follow.

Image sensor and processor. Of course, the image sensor and processor are also an important part of the speed and image quality of the Sony A33. The Sony SLT-A33 has a newly developed Exmor APS HD CMOS sensor, which has a total resolution of 14.6 megapixels, and an effective resolution of 14.2 megapixels. That's just slightly below the 16.7 megapixel total resolution of the A55, which yields its effective resolution of 16.2 megapixels.

The new CMOS image sensor in the Sony A33 features on-chip column A/D conversion, which helps increase readout speed. It also includes the same on-chip analog and digital noise reduction that featured previously in the Sony A900. The Sony A33 also sports an updated BIONZ image processor, with reworked algorithms to allow its signature high-speed burst shooting, plus digital compositing and Full HD movie recording. The Sony Alpha A33 offers sensitivities ranging from ISO 100 to 12,800 equivalents, and can automatically select an ISO sensitivity between ISO 100 and 1,600 equivalents.

Alpha mount. The Sony A33 accepts Alpha-mount lenses from Sony, and is backward-compatible with older Minolta or Konica Minolta A-mount lenses, allowing use of a huge range of both current and historic glass. Compared to single-lens direct view cameras -- even Sony's own NEX series -- this will likely make the Sony A33 a much more attractive proposition for existing Alpha or A-mount photographers. While Alpha-mount lenses can be used on NEX cameras through a mount adapter, they lose their in-body SteadyShot capabilities, whereas the Sony A33 retains this capability with the same lenses. (In an earlier version of this review, we also called attention to the inability to autofocus using Alpha-mount lenses on NEX-series bodies, but this looks to be negated by a forthcoming update for the LA-EA1 mount adapter that will enable Alpha-mount AF on NEX bodies. We've not yet tested this update, and hence can't comment on how NEX and SLT-series cameras will compare in this area.) Sony rates the SteadyShot sensor shift mechanism in the Alpha A33 for between 2.5 and four stops of correction.

Electronic viewfinder. Part of the camera's compact size comes due to another design decision. Unlike past pellicle mirror cameras, the Sony A33 doesn't provide a true optical viewfinder, but instead relies on an electronic viewfinder. It's a sensible decision. The drawback to using the pellicle mirror to provide a viewfinder as past cameras did is that with most of the light being transmitted to the imaging plane, the optical viewfinder is necessarily very dim. As well as providing a viewfinder that's bright enough for low-light use, adopting an electronic viewfinder in the A33's design has allowed Sony to increase the angle of the translucent mirror, compared to the standard 45 degrees of an SLR reflex mirror. This directs the light path for the AF sensor not only upward, but also slightly forward, allowing optimal placement to keep body size to a minimum.

While we don't currently have details on the precise viewfinder type employed by the Sony A33 -- Sony describes it as a 0.46-inch diagonal (0.43-inch effective) Xtra Fine LCD Tru-Finder -- it clearly employs a time-multiplexed method to display red, green, and blue color information at every pixel location, suggesting it is likely a ferroelectric LCD. This differs from traditional LCD displays, which mostly create color information with a cluster of three adjacent red, green, and blue subpixels (commonly called 'dots'), for each pixel location. When compared to standard LCD electronic viewfinders, ferroelectric types bring both advantages and disadvantages. They've proven somewhat divisive in the past, due to their tendency to demonstrate RGB "rainbow" artifacts when you blink or move your eyes, or with fast-moving subjects. On the positive side, though, since each pixel provides full color, ferroelectric LCDs tend to look much smoother and more detailed than their traditional LCD siblings, with less obvious pixel structure. They also tend to have higher refresh rates, and indeed Sony specs the EVF used in the A33 as offering a 60Hz refresh rate. It's not surprising to see such a display adopted by Sony, since Konica Minolta -- the company Sony absorbed to create its DSLR division -- was a particular proponent of their use.

We're pleased to report that the EVF in the Sony A33 provides better dynamic range than most, and does a decent job of preserving highlight detail in high-contrast scenes. The slight distraction caused by the "rainbow" effect is relatively easy to ignore most of the time. Sony specs the EVF as having 1,440,000 dots, of which 1,152,000 are effective in the viewfinder display. We believe that the company is following precedent here, by reporting a dot count as if each pixel constituted three separate color dots, rather than being time-multiplexed. If that's the case, the actual pixel resolution would be 480,000 total pixels, of which 384,000 are effective in the final image.

It's a little unusual to see an effective pixel resolution for an electronic viewfinder, but we believe the reason effective resolution is some 20% lower than the EVF's actual pixel count is that Sony has selected an LCD with approximately a 4:3 aspect ratio, but are only using the central 16:9 aspect ratio swathe of the display. This is likely done both to match the rear-panel LCD display aspect, and also because even with this crop, the EVF already has a generous 1.1x magnification -- much higher than that of most APS-C DSLRs -- and a somewhat tight eyepoint of 19mm from the viewfinder eyepiece (18mm from the eyepiece frame). Were the whole display used, the eyepoint would fall uncomfortably low -- it's already just a little tight for eyeglass wearers. Thankfully, it includes an unusually wide -4 to +4 diopter adjustment range, better mitigating the tight eyepoint for those with eyeglass prescriptions inside this range. It also has a 100% field of view, and three step automatic / manual brightness control.

Translucent mirror (redux). As noted previously, adopting a translucent mirror design has allowed Sony important benefits in terms of autofocus, burst shooting, and body size, and conceivably the removal of one more mechanical component could improve camera reliability, as well. There's no such thing as a free lunch, though, and the translucent mirror design does have some clear disadvantages as compared to existing SLR and SLD designs. Perhaps most significantly, light entering the lens is shared between the autofocus and image sensors at a fixed ratio. In the Sony A33, about 70% of the light makes it to the imaging sensor, while 30% is reflected to the autofocus module. With a traditional SLR, all the incoming light arrives at the image sensor once the mirror is raised, and the same is true of an SLD camera whenever its shutter is open. With less light arriving at the sensor for an equivalent aperture, a translucent mirror camera must either lower its shutter speed, raise its sensitivity (and along with this, the levels of noise, or the amount processing to mitigate it), or some combination of both. An increase in sensor gain to compensate for the loss may explain why we see slightly higher noise levels from the A33 versus the A560, which share the same sensor.

Another potential issue of the translucent mirror design is that with an extra optical surface between the lens and the imager, flare could be increased, and image quality degraded, and indeed we've seen some evidence of this in predominantly dark shots containing bright point light sources, as described elsewhere in this review. There's also another surface for dust to adhere to, and while this would be too far from the image sensor to appear as distinct specks, it could further contribute to issues with flare and reduced contrast. While manual sensor cleaning will now be a familiar process for photographers used to shooting with a digital SLR, cleaning the pellicle mirror is a total unknown. The Sony A33 provides a cleaning mode allowing the sensor to be accessed, and the pellicle mirror itself can be manually raised to facilitate this, but Sony's documentation provides no advice on cleaning the pellicle mirror itself, simply noting that the surface of the mirror shouldn't be touched.

Exposure. The Sony A33 offers a selection of exposure modes commonplace on any DSLR, as well as several more unusual modes. These include Auto, Auto+ (Advanced Auto), Programmed AE, Aperture Priority, Shutter-speed Priority, Manual, Continuous Advance Priority AE, Sweep Panorama, Scene, and Flash Off modes. The Advanced Auto mode acts much like a regular Auto mode, taking control of most settings, but differs from the standard Auto mode in that it can also access some of Sony's more unique multi-shot modes, such as Handheld Twilight and High Dynamic Range. Continuous Advance Priority AE increases the maximum burst shooting speed as compared to the standard Continuous Advance modes, but does so by requiring the aperture be fixed near its open position. The Sweep Panorama mode can function in either 2D or 3D variants, and allows capture and in-camera stitching of multi-shot panoramic images by simply pressing the shutter button and sweeping the camera across the subject. A selection of user-friendly scene modes accessed through the Scene position include Portrait, Sports Action, Macro, Landscape, Sunset, Night view, Hand-held Twilight, and Night Portrait, and let beginners get the look they're aiming for, without needing to understand the subtleties of shutter speeds, apertures, and the like.

The Sony A33 uses the image sensor itself when metering, and considers the overall image as 1,200 separate zones in performing metering calculations. Metering modes include Multi-segment, Center-weighted, and Spot, and the metering system can function from -2 EV to +17 EV (at ISO 100 equivalent with an F1.4 lens). An autoexposure lock button is provided, allowing metering to be locked from a specific portion of the subject, then the overall image reframed as desired. +/-2.0 EV of exposure compensation is available, in 1/3 EV steps. The A33 also offers a three-frame exposure bracketing function, which allows a step size of either 1/3 or 2/3 EV between subsequent frames. Shutter speeds from 1/4,000 to 30 seconds are available, as well as a bulb position that holds the shutter open for as long as the shutter release is pressed. Flash X-sync is at 1/160 second. White balance options include auto, six presets (Daylight, Shade, Cloudy, Incandescent, Fluorescent, and Flash), plus both custom and direct color temperature (2,500 to 9,900K) options. The six presets allow +/- 3 step adjustment, and there's also a color filter setting that provides +/-9 steps of magenta / green compensation.

Flash. The Sony A33 includes an auto-popup flash strobe with a guide number of 10 meters at ISO 100, as well as a proprietary flash hot shoe. The built-in flash has 18mm coverage, and a recycle time of four seconds. Flash modes include Auto, Auto w/ Red-eye reduction, Fill, Fill w/ Red-eye Reduction, Slow-sync, and Rear-sync. Flash metering modes include ADI and pre-flash TTL. +/-2 EV of flash exposure compensation is available, in 1/3 EV steps, and flash exposures can also be bracketed, with three frames varying by 1/3 or 2/3 EV. External strobes including the HVL-F36AM, HVL-F42AM, HVL-F56AM, and HVL-F58AM support high-speed sync and wireless shooting.

Movie mode. The Sony A33 offers high definition interlaced video capture at up to 1,920 x 1,080 pixel resolution, commonly known as "Full HD" or "1080i." While Full HD videos are recorded using 59.94i or 50i interlaced field rates, the actual sensor data is clocked off at a frame rate of 29.97 or 25 frames per second. Using the non-standard 1,440 x 1,080 and standard definition VGA 640 x 480 pixel modes, progressive scan videos are created, matching the same actual sensor frame rates. One quirk of the A33's design is that when shooting VGA videos, the focal length crop is increased just slightly, yielding a video feed that appears to have been shot with a more powerful telephoto lens (and in the process, making wide-angle video harder to achieve). The closely related A55 model doesn't share this feature, which we'd speculate is likely due to some limitation as to how data can be most efficiently clocked off the CMOS image sensor in video mode.

Maximum video length is 29 minutes or two gigabytes per clip, whichever limit is reached first -- although if SteadyShot is enabled, this limit is slashed to just nine minutes per clip, likely due to sensor heating issues when using the sensor-shift stabilization mechanism. Full HD videos are recorded using 17Mbps AVCHD compression, while the lower resolutions are saved with MP4 compression, at a bitrate of 12Mbps for 1,440 x 1,080 pixel video, or 3Mbps for VGA video. Movie capture is started and stopped with a dedicated Movie button located just to the right of the electronic viewfinder, within easy reach of a thumb press.

The most unusual capability of the Sony Alpha A33's video mode is enabled by its translucent mirror. The Sony A33 can continue to use phase detection autofocusing during movie recording, allowing swift adjustments to focus as your subject moves. Since standard Alpha-mount lenses are used, this focusing action is accompanied by significant levels of AF drive noise, which is clearly picked up by the camera in recorded videos. For consumers, this is likely a relatively small price to pay for sharply focused video, however, given that manually pulling focus during video capture is a difficult art to learn. If focus point selection is set to local, the Sony A33 even allows the active focus point to be changed during video capture, and it's also possible to adjust exposure compensation during recording. Also available in Movie mode are the autoexposure lock function to prevent variations in scene brightness, and white balance, creative style, AF area and metering mode functions. However, if autofocus is used, lens aperture must be controlled automatically by the camera, regardless of AF servo mode. When using manual focus, the A33 allows manual control of aperture before video capture commences. In all cases, shutter speed and ISO sensitivity of videos is controlled automatically.

The Sony A33 includes an internal stereo microphone, actually comprising two separate monaural microphones located on either side of the electronic viewfinder / flash housing. It can also accept external stereo microphones, courtesy of a 3.5mm jack on the left side of the camera body. Alternatively, sound recording in videos can be disabled, if preferred. The built-in speaker in the Sony A33 is monaural, and there's no manual control over audio recording levels.

Dust is reduced via a protective film (1) and shaken free by the sensor-shift mechanism (2).

Dust reduction. The Sony A33 has a dust abatement and removal system. A charge-protection coating on the low-pass filter aims to prevent dust adhering in the first place. The sensor shift mechanism used to provide SteadyShot image stabilization also doubles as a shake mechanism to try and free stubborn dust particles that settle on the low-pass filter, although at much lower frequencies than the vibration induced by cameras using a piezoelectric element. From what we can tell, there is no strategy for keeping dust off the translucent mirror, except to blow the surface gently with air; it cannot be cleaned, and should never be touched. A fingerprint would require replacement at a service center.

Fire up the Sony A33's level gauge and you can realign yourself with the world.

Tilt level. The Sony A33 includes a dual-axis level gauge, which helps ensure level horizons and prevent converging verticals in photos. The level gauge can be shown on either the electronic viewfinder or the rear-panel LCD, but only alongside the most basic information overlay -- you can't combine the detailed display overlays with the level gauge. A clever way around it, though, is to set one viewer to the level gauge, and the other to a more informative display, since by default you can set the display modes independently. There's no way for the user to recalibrate the gauge, if they find the factory default to be inaccurate. The gauge is displayed in a style reminiscent of an aircraft attitude indicator, but with a separation of the roll and pitch indicators. When the camera is perfectly level, the pitch indicators and markings at the end of the roll indicator are illuminated in green.

User interface. Sony has retained a similar menu system in the Sony A33 to that previously featured in the Alpha series DSLRs, but incorporating the new database-driven Playback mode from the NEX-series SLD models. The user interface of the Sony A33 is generally clean and easy to understand, with the one major exception being the rather arbitrary segregation of still images and videos in playback mode. Switching between viewing stills and videos requires the user to either enter the menu system, or zoom out to the thumbnail view and select the appropriate tab. Neither option is immediately obvious without reading the manual, and photographers unfamiliar with the interface might believe they'd accidentally deleted the unavailable media, not realizing they were simply in the wrong viewing mode.

Special features. The Sony Alpha A33 incorporates a variety of unusual features that have appeared previously in the company's NEX and Cyber-shot series digital cameras, including Sweep Panorama, 3D Sweep Panorama, Auto High Dynamic Range, and Handheld Twilight modes. Each of these modes automatically captures several images, microaligns them, and then combines them into one image with attributes that couldn't have been achieved in a single still.

The Sweep Panorama modes create lengthy panoramic images with a single sweep over the scene, and do a good job of automatically correcting for uneven panning, although they do sometimes show stairstepping in nearby subjects. The 3D variant is particularly unusual, in that it calculates separate left and right-eye views by comparing the positions of subjects as seen by the left and right sides of the lens. The result is saved as a multi-picture object file containing separate left- and right-eye JPEG views of the scene, for viewing on 3D displays.

Auto High Dynamic Range mode captures numerous images with varied exposure, then creates a single image with much greater dynamic range than would otherwise be possible.

Handheld Twilight mode captures a batch of high-ISO images, reducing blur from camera shake, and then averages the aligned exposures so as to reduce image noise. A new Multi-Frame NR mode acts similarly, but allows the ISO sensitivity to be selected manually, allowing use even at lower sensitivities. Of course, these effects could all be achieved in a PC with some work and know-how, but what's impressive is that they're now available with a minimum of fuss, in-camera. To ensure that even inexperienced photographers can derive benefit from these features, Sony has also created a new Auto+ exposure mode that can identify when these functions might be of use, and then enable them automatically.

Power and card. The Sony A33 uses both SD and Memory Stick Pro Duo cards, and an NP-FW50 battery.

Storage and battery. The Sony Alpha A33 offers a single flash memory card slot, but it's compatible with two memory card standards, each with various permutations. The first is Memory Stick PRO Duo / PRO-HG Duo, Sony's own proprietary media format. As an alternative for those who prefer more standardized media, Sony also supports three flavors of Secure Digital cards -- standard SD, SDHC, and SDXC.

The Sony Alpha A33 uses a 7.2V, 1020mAh InfoLITHIUM battery pack, with part number NP-FW50. Tested to the CIPA standard, the Sony Alpha A33 is rated at the lowest battery life among its SLT-series siblings, with 340 LCD shots, or 270 shots with the EVF. That's perhaps a little surprising, given that it lacks the built-in GPS receiver of the A55V, has a lower-resolution image sensor yielding less data to process, a reduced shooting speed, and less buffer memory. By way of comparison, the A55V captures 380 shots with the LCD, or 330 shots with the EVF, while the A55 can manage 390 shots on the LCD, or 350 with the EVF.

Sony Alpha A55/33 Field Test

by Dave Etchells

Combining breakthrough translucent-mirror technology with Sony's high-speed CMOS sensor prowess, the new Sony Alpha A33 and A55 break important new ground for consumer SLRs. Both deliver higher capture speeds than other consumer-class digital SLR, at 7 and 10 frames per second respectively, as well as true phase-detect live autofocus during video recording. Thrown in multi-shot technology (Handheld Twilight, Sweep Panorama, and Auto HDR modes) brought over from Sony's digicam line, and the new cameras offer features not found in any other SLR, regardless of price point.

I had a chance to spend a few days with a late prototype of the Sony A55 (equipped with production firmware version 1.0) prior to its release. (Note that the Sony A33 is so similar to the A55, that we've only made a few edits to this Field Test to make it work for the A33 review.) After running a couple thousand shots through it (it does have a very fast continuous mode) I found it to be a pretty compelling camera, combining remarkable shooting speed with a host of other capabilities that really set it apart from most of the market. It's by no means perfect, but unquestionably expands the range of shooting capabilities open to consumers with average pocketbooks. Looking at just how much I found to comment on below underscores for me just how much Sony has done in the last few months. Read on for some of my thoughts on this new class of consumer SLR:

In the Hand

Leaving their advanced capabilities aside, the Sony A33 and A55 are also remarkably compact cameras. As we've noted elsewhere, because the mirror in the camera isn't used to form a viewfinder image, it can be mounted at a steeper angle than normal, removing some thickness from the camera body as a whole (the flange-sensor distance must obviously remain the same, but there's more room in the body for the shake-reduction system and other electronics), and the space normally required for the mirror drive system could be trimmed from the sides. As a result, the body is noticeably compact.

I'm always a little torn over really small camera bodies, as it can be uncomfortable to twist my longer-than-average fingers around a small handgrip. That said, I really didn't find the smallish grip on the Sony A55 too objectionable. The design of the front grip naturally encourages my middle and third fingers to curve downward, my pinkie to fold underneath the body, and to carry the weight of the camera on my middle finger, between the second and third knuckle. My customary two-handed SLR grip, with one hand on the lens' zoom ring made for a comfortable and secure hold.

Grip comfort/security is greatly aided by the deeply sculpted thumbrest on the camera's back. Combined with the textured rubber used over the whole right half of the body, it provides a very secure gripping point for my thumb, and does a lot to make up for the small size of the front grip. The rubber coating also contributes to a feel of solid build quality, by damping the body vibrations that often make small and light cameras feel tinny or cheap.

I did find the small body and grip a little problematic when shooting with a long or heavy lens, though: I spent quite a bit of time with the excellent Sony 70-200mm f/2.8 mounted on the camera, and did experience some wrist fatigue by the end of the day. Since the camera is capable of very fast live autofocus during video recording, I often found myself wanting to zoom during the recording, something that would be anathema on a conventional video-capable SLR. Doing so required that I carry more of the weight of the lens/camera assembly on my right hand, so my left could operate the zoom ring more smoothly. The result was a lot of weight for my right wrist to carry, and the small grip made it more difficult than otherwise. When shooting normally with smaller lenses, though, I never found the grip uncomfortable.

The control buttons are for the most part intelligently arranged and readily accessible, but the small space available for them on the right side of the body does mean that you need to hold the camera in your left hand to be able to access them properly: They're really too close to the right side of the camera to keep your fingers wrapped around the grip and operate the buttons with any degree of comfort. On the angled top/back panel, the EV adjust button is perfectly located, right under your thumb, with the AE lock and movie recording buttons on either side of it. The movie button does require a deliberate reach to get to, but is nonetheless easy to identify by feel when you're looking through the viewfinder; just slide your thumb over until it hits the viewfinder housing, and you'll be right on top of the movie button.

Many of the Sony A55 and A33's settings are accessed via the Fn button, just below and the to the left of the thumb grip recess on the back of the camera. I can't think of any better place to put it, but accessing it does require loosening your grip, and therefore shifting support from your right hand to your left. Apart from that, the Fn button is in a good location, easy to find by feel: Just slide your thumb down out of its recess, and the Fn button is the first control you'll touch.

Adjusting settings via the Fn menu is generally a good experience. A very nice touch is that you can use the up/down/left/right directions of the 4-way controller to move the cursor between Fn menu items, and then use the front control dial to adjust the settings. This is nice because it lets you quickly make a number of Fn settings changes in succession, without having to drop down a menu level for each, or being forced out of the Fn menu between choices. The few exceptions to this are those items with a second level of control, such as multi-shot ISO or the tweak adjustments for white balance settings. In those cases, you need to explicitly select the menu item via the OK button, and then use the left/right keys to make the needed adjustment. The only exit at that point is to hit the OK button again, which unfortunately drops you out of the Fn menu entirely.

One nice thing about the Sony A55 and A33's electronic viewfinder is that the Fn menu is also available in the viewfinder display; you can make many camera settings without taking your eye from the viewfinder eyepiece. As I became more familiar with the camera's controls, this led to a very efficient shooting style, although it would take more than the few days I've had with the camera thus far for this to become second nature.

Electronic Viewfinder Display

In reviewing my experience with the Sony A55 and A33, it's interesting to find so many of my notes and so much of my attention directed to the viewfinder display. Were I not already so familiar with Sony's multi-shot exposure technology, the camera's multi-shot features would doubtless have commanded more of my attention, as they're worthy features indeed. That said, though, the viewfinder turned out to be absolutely integral to my experience with the camera.

Nose Relief. The Sony A33's viewfinder eyepiece projects back a bit, leaving a bit more room for your nose.

Where a conventional SLR has an optical viewfinder, the Sony A33/55 substitutes an electronic display with an eyepiece attached. (An electronic viewfinder, or EVF for short.) The image for the EVF is taken from the main image sensor, so the camera is essentially always in "Live View" mode. Mechanically, the eyepiece projects out from the back of the camera a fair bit, to leave room for the camera's autofocus system in front of the EVFs micro display and viewfinder optics. I found I actually liked this rear projection, as it left a bit more room for my nose when I held the camera to my eye. Happily, the neckstrap eyelets are arranged such that the camera hangs lens-down when on a neck strap, so I had no trouble with the projecting eyepiece poking me in the chest.

I have to say up front that I've never been a fan of EVFs. While they do permit much more information overlay than conventional optical viewfinders, I've always felt that EVFs' limitations have outweighed their advantages. In particular, EVFs usually have limited sensitivity and dynamic range, not to mention low refresh rates and poor resolution when compared with the view through a conventional optical viewfinder.

Given my long-term dislike of EVFs, I was surprised to find myself as comfortable as I was with the one on the Sony A55 and A33. It by no means corrects all the ills of the genre, but does go a long way in the right direction. It still loses highlight detail in scenes with both deep shadows and strong highlights, but I found it workable most of the time. I could generally make out clouds against the sky, important for framing landscape shots. It also seemed to do pretty well under low light conditions, although as of this writing, I haven't done a lot of night photography with the camera. Still, the large pixels of the Sony A33's APS-C size sensor mean that its EVF is much more able to form a usable viewfinder image under dim lighting than is that of a typical digicam. Under really dark conditions, I'd still like to see it gain-up a bit more, though, even at the cost of slower refresh rates.

The time-multiplexed full-color RGB pixel technology generally worked well to deliver very high resolution with no gaps at all between the pixels. The only place I was aware of the EVF pixels were in diagonal strokes of letters on the various VF info readouts, or on the electronic level display, when the indicator lines were tilted. I never saw pixel jaggies when looking at the subjects I was shooting, even in the case of sharp high-contrast edges.

The one thing some users might find distracting about the Sony A33's EVF is the RGB "rainbows" you can see when either your eye, the subject, or the camera is moving rapidly. Each pixel of the display shows its red, green, and blue information sequentially, so if the viewfinder image is moving rapidly relative to your eye, you'll see red, green, and blue ghosts or trails around bright objects. I didn't notice this at all until someone pointed it out to me, but after they did, it became unreasonably annoying for a while. After a couple of days of shooting with the camera, though, I again became largely unaware of it and now have to deliberately look for it to be aware of the effect.

On the Sony A33 and A55, the EVF can serve as both shooting and playback display. As mentioned earlier, the ability to check your shots and make camera settings without taking your eye from the eyepiece leads to a slightly different and more efficient shooting style; one that encourages you to learn the camera by feel and memory, rather than looking at the controls as you press them. I've only had a few days with the camera as of this writing, but can see that greater familiarity will produce a very efficient shooting style.

A final benefit of the EVF is that it lets you keep the camera to your eye during video recording, something no other SLR currently offers, although some SLDs do.

I've left perhaps the most salient characteristic of the Sony AF55 and A33's EVF till last: It's huge. The view through the Sony A33's eyepiece is much more akin to that of a full-frame DSLR than that of any competing sub-frame model currently on the market. It manages this with a comfortably high eye point (and plenty of dioptric adjustment) for eyeglass wearers, at least when simply viewing the live viewfinder image itself.

It turns out that the live viewfinder image doesn't cover the full screen in 3:2 aspect mode, but is normally confined to roughly the central 80% of the available display area. When you switch to the Fn menu display, though, you need to press your eye pretty close to the viewfinder eyepiece to be able to see the menu items on the left and right sides of the screen. I found that with my eyeglasses on, I had to shift my eye to the left or the right to see the menu entries on the sides, or else really mash my eyeglasses against the eyecup. Switching to 16:9 aspect ratio expands the image to fill the left and right of the EVF's LCD as well, which is also problematic for eyeglass wearers.

Interestingly, I didn't notice the unusual size of Sony A33's viewfinder display when I first picked up the camera, but I became acutely aware of its loss when I switched back to a conventional sub-frame DSLR after having shot with the Sony A55 and A33 for a day or so. The conventional DSLR suddenly felt I was looking down a tunnel, and I also found myself greatly missing the richness of the A33's viewfinder information overlays. The excellent image quality of the Sony A33's EVF did a lot to win me over to the idea of EVFs on interchangeable-lens cameras, but it was the combination of image size and informational richness that really put me over the top. Because it could appear right there in the viewfinder, rather than on the rear-panel LCD, I was surprised to see how much I came to rely on the electronic level display for keeping my landscape shots straight when there was no obvious horizon line.

Bottom line, while the Sony A33's EVF doesn't entirely conquer the challenges of its genre, it goes further in the right direction than any other I've experienced to date. Most telling is that I now find myself reluctant to give up its benefits and return to world of purely optical viewfinders once again.

Sony A33 Rear-Panel LCD

The potentially game-changing performance of the Sony A33's EVF overshadows its excellent rear-panel LCD, which is a little unfair: It's as good an LCD as is found on any other camera, and in at least one sense literally outshines them all. It's the same widescreen ~920K-dot high-resolution LCD we've seen now on a wide range of cameras from a variety of makers, but its implementation on the Sony A33 adds a couple of useful twists. First, of course, it literally twists and rotates, albeit from the bottom of the body, rather than the side. This unfortunately makes it useless for composing self-portraits with the camera mounted on a tripod, but otherwise is quite helpful for getting over-the-head and ground-level shots with ease.

A bright idea. The Sony A33's LCD screen sports a super-bright "Sunny Weather" mode. It loses some highlights, but makes the viewfinder remarkably usable in direct sunlight. Shot in direct afternoon sunlight, the sequence above gives you some idea of the effect.

The second upgrade to the Sony A33's LCD is the TruBlack technology we first saw on other recent Sony cameras. This is a combination of anti-reflective coatings and a darker mask around the LCD pixels, to keep shadow areas darker. It does seem to be an improvement over LCDs lacking it, but to my eyes, the difference isn't dramatic.

The LCD improvement I found most the most dramatically useful was the brightness settings. Set to Auto brightness, the camera will brighten or dim the LCD display in response to ambient light. This helps a good bit in bright daylight, but the display still washes out in direct sunlight. If you're shooting in bright sun, though, check out the Sony A33's "Sunny Weather" LCD brightness setting. Wow - That's a really bright display! It does blow out the top end of the display's tone curve (that is, you won't see any detail in the highlights in your images in this mode), but this is the first time I can honestly say that I had no trouble viewing a camera's LCD screen in direct sunlight. It's a really great feature, although I'm sure it further reduces the Sony A33's already-short battery life.

Sony A33 High Speed Shooting

As explained elsewhere here, a major point of the Sony A33/55's translucent mirror technology is to permit autofocus operation and image exposure to overlap each other, enabling very fast continuous burst shooting with accurate autofocus tracking. They in fact do a remarkable job of delivering 7fps or 10fps full-resolution shooting speeds, although in some respects, the experience is still rather different than shooting with high-end pro SLRs with that sort of burst capability. The heart of the difference has to do with what image the Sony A33 is showing you through the viewfinder at any given moment.

High-end professional SLRs drop the mirror between exposures, providing a direct (however brief) view of the subject between shots. In contrast, in their highest-speed capture modes, the Sony A33 and A55 display a static image of the shot they've just captured. Rather than seeing interrupted glimpses of your subject in motion, the A55 displays a procession of still images, each lagging the subject motion.

I'm not remotely an experienced sports shooter, so I can have trouble tracking fast-moving subjects under the best of circumstances. Already finding tracking fast action closely challenging, I found tracking fast action closely based on a series of static images delayed by 1/10 second or more was quite a bit harder still. After a little practice, I got better at doing so, but I sometimes found myself resorting to tricks like keeping both eyes open while shooting, or shooting in short bursts and using the time between bursts to get the subject properly framed with full-time live view again.

I found the Sony A33 and A55's AF tracking to be very fast and pretty accurate; almost too fast in some cases: If I let the central AF point wander off the subject for a fraction of a second, focus would quickly shift to the background. Many of the missed-focus shots I took were the result of this problem, versus the camera not being able to track focus quickly enough. Some high-end DSLRs have settings in their autofocus systems to adjust how quickly they respond to momentary loss of the subject. (Either from the AF point drifting off the subject, or for some interfering object passing between the subject and camera.) If Sony were able to add this capability to the A33/55, it could go a long way to reducing the number of missed shots, at least based on my experience.

Fast AF tracking

This sequence gives some idea of the Sony A33 and A55's autofocus tracking ability (these shots were taken with the A55). The subject was a car, approaching the camera at constant rate of 30 miles/hour. In the first shot of the series, the car was perhaps 70 feet from the camera, in the last shot, it's perhaps 15 feet away. Images were shot at a focal length of 150mm, with a Sony 70-200mm f/2.8 G lens. There are a few minor bobbles, but the fourth image of the series was actually blurred by camera motion, not AF error. We shot side by side with the Sony A55 and a Canon 7D, and thought that the A55's AF performance here was pretty similar to that of the much more expensive Canon.

While the Sony A33 and A55's viewfinder display led to a bit of a learning curve for tracking fast action, its buffer-clearing speed is an ongoing issue. The A55 can capture shots with amazing speed, but once its buffer is filled, things slow down dramatically. The A33, for its part, has a smaller buffer, but it takes less time to clear. The most irritating point with the A55 was that it seemed to take forever before it would let me look at what I'd just shot. This is certainly more of an issue for a relatively inexperienced user than a pro sports photographer, but I often found myself wanting to check out what I'd just shot before the next action sequence started so I could note and correct for any problems in my shooting style. If I'd filled the buffer, though, it took upwards of 15-18 seconds before I could even view the first image on the LCD -- and a good while longer before the buffer was completely empty and the camera was back to its maximum burst-length capacity. Shoot RAW+JPEG and it takes 32 seconds to clear a maximum of 18 images, while the A33 only captures 7 images and takes 12 seconds to clear. Advantage A33.

This dead-screen issue was so pronounced that I found myself dropping back to 6 fps rather than 10 on the A55, and shooting in short bursts at what I thought (hoped?) were the decisive moments. More than with many cameras with lesser speed or buffer capacity, I found myself shooting to manage the camera's buffer, more than simply focusing on the subject and the action taking place. It would have been a lot less aggravating if I could have at least seen thumbnails of just-captured shots immediately after taking them.

For all my complaining about the difficulty of tracking sports subjects and the dead-screen issue, though, the difference between these SLTs and other consumer-level DSLRs is little short of astonishing. It may not be a direct substitute for a Canon 1D Mark IV or Nikon D3s, but if you have a budget of under $1,000 and shoot any fast action at all, the Sony A55 and A33 are hands-down slam-dunk purchase decisions. At this point, there's nothing else in the large-sensor segment of the digital camera market that remotely approaches their high-speed capture capabilities.

Sony A33: Speed isn't just for sports

This is an important enough point that I felt it deserved its own heading: High speed shooting isn't just about sports photography; it's about capturing the perfect moment, regardless of how fast the subject is moving. This is a point I've been making since I first tested a prototype of the Casio FH20 a couple of years ago: The difference between the perfect moment of blowing out the birthday candles and one that's a near miss can be a small fraction of a second. When shooting candids of people chatting and interacting, facial expressions and mouth positions change in literally the blink of an eye. A camera that shoots at 7 frames per second vs. one that only manages 3 frames per second can mean the difference between dozens of "keepers" and just a few.

If you enjoy people photography and delight in taking photos revealing real character and emotion, get yourself a Sony A33 and a large memory card, set the camera to high-speed continuous mode, and let fly. You'll be amazed at how much more intimate and impactful your photos become.

Special "Sony" modes

Steady in the dark. The Sony A33's Handheld Twilight (HHT) mode uses multiple shots and micro-alignment to permit handheld exposures even in very dark conditions. This was a very dark bar scene, but the shot came out sharp enough for a 5x7 print. It could have used some exposure adjust and (definitely) a different white balance setting. Exposure is auto-only in HHT mode, but the similar multi-frame NR mode gives full control.

While the Sony A55 and A33's singular claim to fame is its exceptional shooting speed, that's only part of what it has to offer. Just in the last year, Sony has used its high-speed sensor technology to create a number of innovative new camera features that, on their face, have nothing to do with high-speed shooting. This hands-on report is already running far too long, so I'll just make brief mention of some of these special Sony modes here. Even if you feel no need for 7 to 10 fps capture in your personal shooting, these special exposure modes alone would be reason enough to buy one of these cameras.

Handheld Twilight mode

We first saw this feature in Sony's DSC-TX1 and DSC-WX1 in mid-2009. Since then, it's been mimicked by other manufacturers, but none seem to do it as well as Sony. In Handheld Twilight mode, the camera captures up to 6 shots in rapid succession, micro-aligns them with each other, and then adds them all together. The net result is that you can hand-hold ridiculously long exposures and still get sharp results, with very low image noise to boot. Combine this with Sony's SteadyShot image stabilization and sharp handheld photos at half-second exposure times are feasible.

Personally, I find Handheld Twilight mode to be one of the most useful camera features I've seen in recent memory. The freedom to shoot handheld under dim lighting is enormously liberating, opening up lots of photo opportunities that I'd have had to pass on previously. It's the reason I frequently grab a Sony camera for snapshots when I'm going on a personal outing.

Multi-Frame Noise Reduction mode

Handheld Twilight is a scene mode on the Sony A33 and A55, so it doesn't offer you much control: The camera picks the ISO setting, shutter speed, etc, that it thinks is best, and takes the picture. About all you can control is whether to enable face detection AF or not. For those wanting the multi-shot advantages but with more creative control, Sony offers Multi-Frame Noise Reduction mode. This mode lets you select the ISO you want to use, but the camera micro-aligns and averages together six shots, significantly reducing ISO noise. You get the same basic capability as in Handheld Twilight mode, but retain full control over other exposure parameters.

In-Camera Panoramas: Two Sizes

One of Sony's nifty tricks is their in-camera "sweep panorama" technology. The A33 and A55 let you shoot panoramas with the camera held either vertically or horizontally. The vertical orientation makes taller/narrower panoramas that are 5,536 x 2,160 pixels, as seen in the top photo above. With the camera held in landscape orientation, panoramas are 8,192 x 1,856 pixels.

Sweep Panorama

If Handheld Twilight and Multi-Frame NR modes are practical, Sweep Panorama is just plain fun. I've always been a fan of panoramic images, and spent more time than I care to remember back in the film days slicing and splicing together 4x6-inch prints with a razor blade and rubber cement, to make panoramas from sequences of individual shots. The Sony A33 and A55's Sweep Panorama mode does all this for you inside the camera. Again taking advantage of Sony's high-speed capture technology, Sweep Panorama collects dozens of individual images while you hold down the shutter button and "sweep" the camera from side to side or up and down. The powerful Bionz image-processing engine examines all these images, takes slices from each, applies geometric and tonal corrections to each slice, and then stitches them together into a single panoramic image. The results are stunning, and experimenting is loads of fun.

Pretty slick, but not infallible
The camera can't always perfectly compensate for how you move the camera during the panorama, nor for extreme perspective shifts, so you'll sometimes see "stitch errors" in the assembled shots. The slight "stuttering" above left in a shot from the Sony A55 is typical of the mild errors that sometimes occur: Pretty unobtrusive, unless you really zoom in to pixel-peep. More dramatic errors like the crop from an A560 panorama seen above right were fairly rare in my experience. This is a great feature for dramatic vacation snapshots, but if you're making panoramas professionally, you'll still want to build them manually from separate shots.

Sweep Panorama mode makes shooting panoramas easy, but not entirely brainless: It often takes me a few tries to get just the shot I want. The camera throws away a fair bit of the image area top/bottom and left/right, to insure that it has enough room to get everything aligned properly, despite your having angled the camera or not having swept perfectly horizontally or vertically. Sometimes, you can end up with your main subject higher or lower in the frame than you'd anticipated. It's also easy to get a tilted horizon, if the camera orientation or your sweep direction is a little off. I found the A33 and A55's level indicator and viewfinder gridline displays very helpful for avoiding these problems, although there was a little learning curve for me to make effective use of them.

3D Sweep Panorama

In case you hadn't noticed, 2010 is the Year of 3D in the HDTV space, and all the television makers are rushing to add 3D capability across their product lines. Sony has come up with a clever way of capturing 3D images using the same "sweep" technology as in their normal 2D panoramas. As the camera is swept across a scene, it will naturally see various parts of the subject from slightly different angles at different points along its sweep. Sony's engineers have taken advantage of this to add a 3D Sweep Panorama mode to a number of their cameras, the A33 and A55 included. While the 3D data is apparently stored in a fairly standard file format, viewing the 3D images currently requires connecting the camera's HDMI output to a Sony 3D-capable television set. Sony's promised 3D Sweep Panorama playback support for their PS3 game consoles, supposedly coming as early as this September. That's still a bit limiting, but hopefully as 3D technology matures, various manufacturers will be able to read each others' 3D formats.

If you have a 3D-capable Sony television to view them on, capturing 3D images can definitely be entertaining. That's about where I'd leave it, though: "Entertaining" vs "compelling." While you do get a reasonable 3D effect in shots captured this way, I found the quality of the 3D experience a little disappointing. Don't expect Avatar-level 3D, this strikes me as more of a gee-whiz sort of feature: In my experience, the 3D effect is a bit limited, and foreground objects tend to break up visually. I suspect this has to do with the fact that the perspective is changing throughout the sweep, so things like effective intraocular distance and viewing angle aren't perfectly consistent throughout the image. Whatever the cause, it's a fun effect, but not something that would be a decisive factor for me in choosing a camera, whereas ordinary 2D sweep panorama is something that I've used often. (Personally, I suspect this feature has a lot less to do with selling cameras than it does with selling TVs: I wouldn't buy a camera for the feature, but all else being equal, if I owned a Sony camera that had the feature, I'd be more inclined to purchase a Sony television that supported it.)

Tonal Extremes? Not a problem...
DRO Off	DRO Auto	Auto HDR, 6 EV
The Sony A33 offers a lot of control for shooting contrasty subjects. Dynamic Range Optimizer (DRO) adjusts contrast and brightness to optimize the camera's use of available dynamic range. Auto HDR modes use three quick shots to cover an amazing tonal range. (The shot on the right represents the maximum range of 6 EV.)

Auto HDR

There's one more multi-shot feature on the Sony A33 that's worth mentioning; namely Auto HDR (High Dynamic Range). HDR photography increases the range of brightness values represented in a scene by combining two or more shots taken at different exposures, combining highlight detail from some and shadow detail from others. In the past, this has involved locking the camera down on a tripod, shooting several images at different exposures, and then working on a computer to combine them. Lately, though, the capability to do this directly in-camera has been appearing from a number of manufacturers, with varying levels of success. The auto HDR feature on the Sony A33 works pretty well, since the camera does the same micro-alignment trick it uses for its other multi-shot features. Options for HDR include an Auto setting, where the camera determines how much of the effect to apply, and manual settings ranging from 1 to 6(!) EV of exposure range.

HDR is a feature that's easy to over-use, as it can quickly over-flatten the contrast of an image, resulting in a dull, lifeless photo. On the other hand, there are times when nothing else will do. I've shot a lot of landscape images over the years where I've really wished I had it; situations where there was bright sky and deep shadows, or a bright rockface but also interesting detail I wanted to capture that was in the shade. With an auto-HDR option, I often find myself trying it, but also shooting a normally exposed shot as well. I more often like the normal shot, but sometimes the HDR one is the keeper. (I really wish there were an option to have the camera capture three shots; a normally-exposed one and the the high/low exposure pair it uses to build the HDR image from. It'd be handy to be able to shoot a normal image, with the HDR shot as backup.)

Sony DRO (Dynamic Range Optimization)

Actually, while HDR is the more glamorous feature, Sony's Dynamic Range Optimizer (DRO for short) deserves some attention, as I found myself relying more on it than HDR to manage tonal extremes. Most every camera company has some sort of an exposure mode that adjusts exposure and/or contrast to help avoid blowing highlights or plugging shadows. After several years of tweaking, I think that images shot with Sony's DRO now look better than most. DRO defaults to the Auto setting on the Sony A33 and A55, and most times I checked, I liked the tonal balance of photos shot that way over that those with DRO turned off.

Sony A33 Video Shooting

Fast AF. Phase-detect AF doesn't hunt like contrast-detect, making for fast, smooth AF during movies. (Click to download 4.9MB MP4 file.)

Video capture is an area where the Sony A33's translucent mirror technology makes a huge difference relative to pretty any other SLR currently on the market, and relative to even fast-focusing SLDs. Every other interchangeable-lens camera currently on the market either doesn't autofocus at all when recording videos, or has to resort to slower and/or more obtrusive contrast-detect focusing. Because the Sony A33's phase-detect AF system is always looking at the subject, fast autofocus during video recording is no problem.

Phase-detect AF isn't just faster, though, it's much less noticeable in your videos. Because phase-detect AF actually measures the amount of mis-focus, it can command the lens to go directly to the correct focus setting, without "hunting" back and forth. By comparison, contrast-detect AF has to try different focus settings one after another, checking to see whether each amounted to better or worse focus than the one that preceded it. This can be quite distracting in the recorded video, as you can visibly see the focus shifting back and forth, even when the subject isn't moving. Have a look at the video above left which shows pretty fast, sure-footed focus when the subject is changed. (See our Sony A33 Video page for more details and sample videos.)

It's not all a bed of roses with video and live AF on the Sony A33, though. While it tracks action very well, focus actuation with the kit lens is far from silent: In anything but a very loud environment, the "chock... chock" of the lens' focus operation is painfully apparent in the audio track. Even with the ultrasonic motor-equipped Sony 70-200mm f/2.8G lens attached, focus noise was quite audible in quiet environments. Another really annoying (and entirely avoidable) audio artifact is the loud click that's recorded at the very end of each video clip; the sound of your pressing the video on/off button to stop the recording. I experienced this with the NEX-5 as well, and it honestly seems like a bug to me.

Overall, there's little question that the Sony A33 has the best video AF of any interchangeable-lens camera currently on the market, but if you plan on doing much video recording, I'd suggest you also plan on buying an accessory external microphone to record the audio.

Sony A33 Exposure Accuracy

Some adjustment necessary. This shot turned out well at -0.3 EV, but a lot of my shots under bright conditions could really have used -0.7 EV of adjustment.

While we didn't encounter any exposure accuracy issues in our lab tests, I had a little trouble with the Sony A33 and A55's exposure system in the field. Under bright sunlight, I was generally shooting with -0.3 EV of exposure compensation dialed in. Looking at my photos on the computer later, it seemed that many of them really could have used -0.7 EV. The overexposure bias seemed fairly universal under bright lighting, regardless of whether the subject itself was low- or high-key. Shots under lower lighting didn't seem to have the same issue, though.

Besides the overexposure bias, I also found the A33's metering system was prone to more variation than I'm accustomed to seeing in an SLR. The few times I had it locked down on a tripod, shot to shot exposure seemed pretty consistent, but on several occasions shooting handheld, I found significant variation between successive shots, apparently resulting from fairly minor changes in framing. I'd of course expect exposure to vary to follow changes in the scene, but the amount of variation I saw between very similar shots taken with the A33 was unusual.

Sony A33 Battery Life (or not)

The one negative that most stands out in my mind for the Sony A33 actually has the least to do with its abilities as a camera. The first thing that comes to mind when thinking about shooting with it isn't whether I'll be able to bring back the shots I want with it, but rather whether the battery will last long enough to do so. We have no doubt that the Sony A33 will meet the fairly generous shot-life numbers quoted under the CIPA specs (340 shots with the LCD, 270 with the EVF), but in actual practice, with the camera rattling off hundreds of shots in amazingly short order, what most struck me was just how fast I seemed to run out of battery life. It's quite easy to run through a full battery in just a couple of hours of active shooting, and two batteries should be considered a minimum for a day of serious shooting.

In the old days, we were always careful to remind readers to purchase a second battery along with their camera, but in recent years, battery life has become much less of a concern than it once was. Not so with the Sony A33, though: Unless you intend it only for light snap-shooting, consider the purchase of a second battery mandatory.

In the Box

The retail kit contains the following items:

• Sony Alpha SLT-A33 body
• SAL-1855 SAM lens
• Lithium-ion battery pack NP-FW50
• Battery charger BC-VW1
• USB cable
• Body cap
• Lens cap
• Shoulder strap
• Software CD-ROM

Recommended Accessories

• Extra battery pack for extended outings
• Fast, large capacity SDHC memory card. These days, 4GB is a good tradeoff between cost and capacity, but if you plan to capture many movie clips, 8GB should be a minimum.

Sony A33 Conclusion

While I found enough to quibble about to justify my role as a reviewer, I also found the Sony A55 and A33 to be uniquely compelling cameras. The most telling point was how hard I found it going back to an "ordinary" SLR after just a day of shooting with the A55. I've long been an avowed EVF-hater, but the viewfinder display on the Sony A55 is good enough that I found myself sorely missing it when I returned to shooting with a conventional sub-frame SLR with a typically small optical viewfinder. The Sony A55's shooting speed matches that of professional models costing literally thousands of dollars more thanks to the unique pellicle mirror design, and its uniquely Sony features (Handheld Twilight/Multi-Frame NR and Sweep Panorama modes in particular) take the A55 places no other SLR has gone before. I was also pleasantly surprised by how comfortable the Sony A55's grip was, given the tiny body size. I still prefer having more to wrap my fingers around, but this is as good a grip as I've seen on an SLR body this compact to date. While its primary target clearly is not the entry-level shooter, the Sony A55's Auto+ mode takes it closer to true "just push the button" simplicity in auto mode than any other camera we're aware of, enabling novice-level users to enjoy the multi-shot and other Scene modes without having to worry about which to use when. At the other end of the spectrum, for the enthusiast with time to become acquainted its capabilities and familiar with its quirks, the Sony A55 expands the realm of amateur photography further than any SLR to date. In the A55 and A33, Sony has used outside-the-box thinking to deliver a uniquely capable, functional, and well-designed SLR. Hot on the heels of their category-redefining NEX-3 and NEX-5, Sony's engineers have now likewise redefined what consumers can expect from an SLR.

For maximum resolution and shooting speed, plus built-in GPS, choose the Sony A55. Give up a little speed and resolution and drop the GPS, though, and you can save upwards of $200 with the Sony A33.

Design

Sony Alpha A33 Design

Roll-over the various controls and features with your mouse for a brief description. Note: Rollovers are best viewed with the latest versions Firefox, Safari, or Opera browsers, or Internet Explorer 6 or earlier.

Sony A33 Front. Only a couple of controls are to be found on the front of the Sony A33. These include the Control dial at the top of the handgrip, the Lens Release button just to the right of the lens mount, and the Depth of Field Preview button at the lower left of the lens mount. The short vertical plastic strip in the handgrip hides a self-timer lamp at its lower end, and also conceals the infrared receiver for use with an optional remote control.

Sony A33 Left Side. This side includes a button to raise the built-in flash strobe, a focus mode selector switch that's only functional when the lens attached to the camera doesn't have its own duplicate switch, the left-hand microphone on the side of the viewfinder / flash housing, and three compartment doors behind which the microphone jack, wired remote, HDMI, and USB connectors can be found.

Sony A33 Right Side. From this angle, the Sony A33 is free of controls, with the only notable feature being the right-hand microphone on the viewfinder / flash housing. You can also see the diopter adjustment dial, tucked just inside the bottom of the viewfinder eyecup.

Sony A33 Top. Many of the A33's controls are to be found on its top panel. These include the power switch, shutter button, and mode dial, as well as D-Range button (which accesses dynamic range expansion and high dynamic range-mode options), and a Finder / LCD button (which switches between using the electronic viewfinder, or the rear-panel LCD display). The A33 can also switch between displays automatically, using a proximity sensor located just below the viewfinder eyepiece; it isn't possible to use both displays at once. Angled for good visibility either from above or behind the camera are four more buttons -- the Menu, Movie shutter, Exposure Compensation, and Auto Exposure Lock buttons, respectively..

Sony A33 Back. The rear panel of the Sony A33 is dominated by a 3.0-inch, 921,600 dot LCD display mounted on a mechanism that allows it to be tilted downwards 180 degrees, and swiveled 270 degrees. Controls on the camera's rear include a four-way controller with central OK button, as well as the Function, Playback, and Delete buttons. The Function button calls up a Function menu, providing quick access to adjust common exposure variables. With space at a premium, the four-way controller and OK button are only labeled with their Record mode functions, with it being left to common sense (or reading the manual) to ascertain that it's also used to make menu selections, browse captured images and movies in playback mode, and pan the image when using playback zoom.

Sony A33 Bottom. There's not a lot to see on the base of the Sony A33, beyond the metal tripod mount (centered on the lens' axis), and the battery / flash card compartment door. The door contains a small cutout flap that provides an entry point for the optional AC adapter's dummy battery cable. The single flash card slot is dual-format, accepting either Secure Digital or Memory Stick PRO Duo media. SD cards are inserted with their electrical contacts facing the front of the camera, and Memory Stick PRO Duo cards with their contacts facing the rear. A card access lamp is just barely visible immediately above the left-hand end of the LCD display in the picture above.

Operation

Sony A33 Operation

The Sony A33 relies on a large, color LCD screen and electronic viewfinder for all user interaction, with its compact size not leaving room for the small LCD info displays that are common on many full-sized SLRs. Both the LCD display and electronic viewfinder provide the same user interface experience, which is clear and highly visible, making it very easy to switch back and forth between display types. The drawback is that since one or other display type is always active when the camera is in use, this must contribute to reduced battery life. One feature we do like very much is the infrared proximity sensor that switches off the LCD screen when you hold the Sony A33's electronic viewfinder up to your eye.

Menus can be navigated either by using the four way arrow pad, or by turning the control dial. The button in the center of the four-way arrow pad makes selections, although with little room on the camera body, there are no markings on the arrow pad and central button to indicate these functions. The control dial is also used to adjust shutter speed and aperture in Manual or Priority exposure modes. Since there's only one control dial and two variables to adjust when in Manual mode, the Exposure Compensation button is held in to switch between the two variables. In other record modes where Exposure Compensation is available, the same button allows adjustment of the compensation amount, and an autoexposure lock (AEL) button fixes the curent exposure level while held down, allowing a metering reading to be taken, and then the subject reframed as desired. The left and right arrow buttons respectively access the drive mode and white balance dialogs, while the up arrow changes the display type, and the down arrow calls up the ISO sensitivity dialog. A dedicated Movie button is used to start and stop video recording, separate from the still image Shutter button. A Depth of Field Preview button adjacent to the lens mount will stop the lens down to the selected aperture while held in, allowing depth of field to be confirmed visually.

Record Mode Displays

Full-time Live View
The information display in record mode includes the shutter speed and aperture settings, exposure compensation level, exposure mode, flash mode, ISO sensitivity setting, metering mode, AF mode, number of available images, resolution for still images and movies, compression for still images and movies, aspect ratio, image stabilizer mode, drive mode, white balance, creative style mode, Face detection / smile shutter modes, DRO / HDR modes, focus confirmation, battery status, etc. As you change exposure settings, the display changes to reflect what the captured image will look like, also known as "exposure simulation." A graphic display mode allows you to see both shutter speed and aperture represented on gauges showing their current position relative to the available range for each exposure variable. You can also enable a live histogram. Through the Setup menu, you can enable a rule-of-thirds grid display. See the illustration below (courtesy of Sony America) for information callouts in record mode.

Sony A33 Record Mode Displays
Section 1
	Exposure mode		Image quality of still images
	Memory card		Image size of movies
	Remaining number of recordable images		Remaining battery
	Image size of still images / Aspect ratio of still images / Image size of panoramic images		Overheating warning
	Database file full / database file error		Camera shake warning
	No audio recording of movies		GPS triangulating status
Section 2
	Spot metering area		AF area
	Shutter speed indicator		Aperture indicator
Section 3
	Recording time of the movie		EV scale
	Focus		AE lock
	Shutter speed		SteadyShot scale
	Aperture
Section 4
	Drive mode		AF area
	Flash mode / red-eye reduction		Face detection
	Focus mode		Smile shutter
	Smile detection sensitivity indicator
Section 5
	ISO sensitivity		Metering
	Flash compensation		White balance (auto, preset, custom, color temperature, color filter)
	D-Range optimizer / auto HDR		Creative style

Sony A33 Record Mode Displays
Section 1
	Exposure mode		Image size of movies
	Memory card		Remaining battery
	Remaining number of recordable images		No audio recording of movies
	Image size of still images / Aspect ratio of still images		GPS triangulating status
	Image quality of still images
Section 2
	Flash mode / red-eye reduction		Face detection
	Drive mode		Smile shutter
	Focus mode		AF area
	ISO sensitivity		White balance (auto, preset, custom, color temperature, color filter)
	D-Range optimizer / auto HDR		Creative style
	Metering mode		Exposure compensation / Metered Manual
	Flash compensation		EV scale
Section 3
	Shutter speed		Aperture
	Exposure		AE lock
	SteadyShot

Playback Mode Displays

Information Screens
In Playback mode, the default image display shows the most recently captured image or movie. Pressing the Up arrow (Disp) button cycles through the main display (with no information), a simplified display with basic information overlay, and a detailed thumbnail display with RGBY histogram, shooting info and blinking highlight/shadow display (overexposed areas are shown in black, underexposed in white). The most recent display type will be stored and shown the next time by default. Pressing the Right or Left arrow displays the next or previous image (if currently viewing a still image) or movie (if currently viewing a movie). Curiously, there's no direct way to switch between viewing movies and still images. Instead, you must either go to the Index view (described below), then select the Movie or Still Image tabs at the left of the screen, or enter the Playback menu, then select the relevant type in the Still / Movie Select option.

Index View
Pressing the Exposure Compensation (Zoom Out) button switches to an Index view of either still images or movies -- but not both at the same time. You can view either six or twelve thumbnails on screen at once in Index view, but changing the number of thumbnails involves eight button presses to get to the Playback menu, and change the Image Index option. The Left, Right, Up, and Down arrow buttons move between the image thumbnails, and rolling the Control dial has the same effect. The soft key at the center of the four-way controller selects an image or movie for viewing. The Delete key deletes an image or movie. Two tabs at screen left are used to change between viewing still images, or viewing movies, since the A33 can't display both types at the same time.

Magnified View
Pressing the AEL (Magnify) button while viewing a single still image in Playback mode switches to the magnified view. Unless viewing a panoramic image, once in this view, you can press the Magnify and Zoom Out buttons to zoom in or out as much as 11.8x, while pressing the arrow buttons pans around the image. The Playback button exits magnified view, and the Delete button deletes the magnified image (after a confirmation screen), then returns you to full image view. For panoramic images, the first press of the AF (OK) button scales the panorama to fit the screen on its shorter side, then pans the length of the panorama automatically once, before returning you to full image view. Pressing the OK button while the panorama is panning will pause the display, at which point you can enter magnified view by pressing the Magnify button. This then allows you to pan and zoom exactly as you would with any other still image.

Movie Playback
Pressing the OK button while viewing a single movie in Playback mode launches movie playback. A second press will pause movie playback, and a third press will resume it. While the movie is playing, rotating the Control dial will cue forwards or backwards through the movie. Pressing the Down arrow button while paused brings up a volume adjustment control, allowing the volume to be adjusted within a seven step range, or the video muted altogether, by either turning the Control wheel or using the vertical arrow buttons. The Delete button deletes the magnified video (after a confirmation screen).

Optics

Sony A33 Optics

Alpha lens mount. Despite the new translucent mirror design, the Sony A33's Alpha lens mount is compatible with the full array of Sony Alpha and most Konica Minolta AF lenses, both screw-drive and electronic autofocus models.

The Sony A33 features a bayonet lens mount, which accommodates a range of Sony and Konica Minolta AF lenses. The Sony A33 is available in two versions -- body only, and bundled with a Sony DT 18-55mm f/3.5-5.6 SAM kit lens. For additional test results, see our review of this lens on SLRgear.com. A small button on the front of the camera releases the lens from its mount, so it can be turned and removed. The A33's CMOS sensor is smaller than a 35mm frame, so the angle of view at any given focal length will not be the same as on a 35mm camera. To find the approximate 35mm equivalent focal length, multiply the focal length of the lens by 1.5. (Thus, a 50mm lens will provide about the same view as a 75mm lens on a 35mm camera.)

Sony A33 Autofocus

The Sony A33 provides both manual and automatic focus control modes, set by the Focus Mode switch on the left side of the camera body, unless the lens itself has a Focus Mode switch. If there's a duplicate switch on the lens, it takes over this function, and the one on the body serves no purpose. With whichever switch is applicable, you can select between Auto and Manual focus modes. The Function button provides access to additional AF modes and AF Area options. The Autofocus Mode option under the Function menu offers Single-shot AF, Automatic AF and Continuous AF settings. Single-shot sets focus with each half-press of the Shutter button, while Continuous mode is constantly adjusting the focus, whether the Shutter button is pressed or not. The Automatic setting will lock focus on a still subject or continually adjust focus on a moving subject, for as long as the Shutter button is halfway pressed.

Autofocus Area also has three options available through the Function menu: Wide, Spot, and Local (manual setting). The default option is a fifteen-point Wide Focus area, indicated by an array of square focus areas inset within four widely-spaced brackets in the viewfinder image. (Note that only three points at the horizontal center of the frame utilize a cross-type sensor, sensitive to detail in both the horizontal and vertical axis. The other 12 sensors are line-type, sensitive to detail in one direction only.) Wide AF bases its focus on the most prominent subject detail in the portion of the image that falls within the AF brackets. Spot mode bases its focus on the very center of the frame, where the square target resides. The Local setting is Sony's terminology for a manual AF area selection, and lets you manually set the main AF point by using the Multi-controller to highlight one of the fifteen AF points. The selected AF area is indicated with an orange frame during selection, and with a black frame in the viewfinder while framing images, while unselected points have a light gray frame.

A depth-of-field preview button can be found adjacent to the grip, at the base of the lens mount. When held in, the A33 stops down its aperture to the selected value, and adjusts preview sensitivity to attempt to show the image with correct brightness.

Sony A33 AF Assist

The Sony A33 uses its built-in flash head as an AF-assist light for better focusing in dim lighting. This has the advantage that the light from the flash is very bright, but the downside is that it's rather distracting, and you can only get AF assist when the flash head is raised. This is a real limitation for available-light photography, as the camera can expose at light levels well below those it can focus at. (Although its low-light focusing ability is much better than average.) If the camera is fixed on a tripod, you can work around this limitation, but it's somewhat awkward: With the flash head up, half-press the shutter button to make the camera focus. Then switch the focus mode to manual focus, being careful not to touch the focus ring on the lens. Stow the flash head, and then take your picture. (But don't forget to switch back to AF mode for the rest of your shooting!)

Sony A33 Anti-Shake

The Sony A33 also employs Sony's Super SteadyShot anti-shake technology, which uses a highly sensitive accelerometer and image sensor shift mechanism to move the sensor assembly itself to counteract camera movement, rather than the more common approach of moving an optical element inside the lens. Sony claims that the Super SteadyShot anti-shake system in the A33 provides a 2.5 to 4-stop reduction in the blurring produced by camera shake. Even the lower end of the specified range of effectiveness means a pretty significant improvement in one's ability to hand-hold long exposures.

When Super SteadyShot is activated, the SteadyShot scale on the right side of the viewfinder display indicates the degree of stabilization. What's more, because the A33's LCD and EVF display the image as seen by the imaging sensor, the effect of SteadyShot stabilization at work can be seen, unlike models that use a traditional optical viewfinder. The SteadyShot scale is still useful even with the stabilized view though, as it gives you a good idea of how hard the SteadyShot mechanism is working, so you can choose a moment when the camera is moving less to snap the shutter, thus maximizing your chances for a sharp image.

Sony A33 Anti-Dust Technology

To help combat dust particles on the sensor from changing lenses, Sony included both an anti-static coating on the sensor filter and anti-dust vibrations to automatically shake the sensor with the anti-shake mechanism each time the camera is shut off. There is also a manual cleaning mode, where the camera opens the shutter, allowing access to the sensor for use with a blower or other cleaning device. The Translucent Mirror must be manually raised to access the image sensor, and it's important not to touch the mirror in the process. There's no user method for cleaning the mirror itself, with the only option if this is required being to return the camera to Sony for service.

We've generally found dust-removal systems based on cameras' anti-shake systems less effective than those that use an vibrate the sensor ultrasonically, but it bears noting that no dust removal system completely eliminates the need for occasional manual sensor cleaning. Copper Hill Images is an advertiser of ours, but we'd recommend their wet/dry cleaning system even if they weren't (it's what we use in our own lab): See the Copper Hill website for details.

Sony A33 Optical Test Results

Below are the results of our optical tests with the Sony A33 and the bundled 18-55mm kit lens.

Lens Test Results

Zoom
Decent performance with the 18-55mm kit lens.

The Sony SLT-A33 is available bundled with a 18-55mm f/3.5-5.6 SAM lens. This lens possesses a very typical optical zoom ratio of about 3x, with a 35mm equivalent focal range of about 27-83mm because of the A33's 1.5x "crop factor". Results were good at 18mm with strong detail across most of the frame, though there was some minor softening in the corners, even at f/8. Coma distortion in the trees was low in the corners, but chromatic aberration was moderately high along high contrast elements near the edges of the image. Results at the 55mm setting were sharp in the center and bottom of the frame, but the top and left hand-side were soft. Chromatic aberration at full telephoto was negligible. Overall, decent results for a kit lens.

Macro
An average sized minimum coverage area, with good detail. Flash throttled down well.

As with zoom performance, the Sony A33's macro performance will depend entirely on the lens in use. However with the 18-55mm kit lens set to 55mm, the Sony A33 captured an average sized minimum area measuring 2.33 x 1.55 inches (59 x 39 millimeters). Detail was quite good in the center, though the corners were moderately soft. (Most lenses have some softening in the corners at macro distances.) The flash throttled down well, resulting in a good exposure if slightly bright. The flash also had no trouble clearing the lens as there is no detectable shadow, though the bottom of the image is slightly darker than the top.

Geometric Distortion
Higher than average geometric distortion at wide-angle, very low at telephoto.

Barrel distortion at 18mm is 1.1 percent

Pincushion distortion at 55mm is less than 0.1 percent

The Sony A33's 18-55mm kit lens produced about 1.1 percent barrel distortion at wide-angle, which is higher than average and noticeable in some of its images. At the telephoto end, there's less than 0.1 percent pincushion distortion, which is practically non-existent. This is the tendency for the lens to bend straight lines outward (like a barrel -- usually at wide-angle) or inward (like a pincushion -- usually at telephoto).

The Sony A33 does not appear to be applying any geometric distortion correction to its JPEGs, as uncorrected RAW files show the same amount of distortion.

Chromatic Aberration and Corner Sharpness
Moderately high chromatic aberration at wide-angle; lower levels at full telephoto. The lens produced some soft corners, especially at wide-angle.

Chromatic Aberration. Chromatic aberration in the corners with the A33's 18-55mm kit lens at wide-angle (18mm) is moderate in terms of the number of pixels, but quite bright, so the effect is noticeable in some shots. At full telephoto (55mm), C.A. is also moderate in terms of pixels, but the colors in the fringes are quite muted, partially due to a loss of contrast. Color fringing gradually reduces in brightness and width as it approaches the center of the image, where it is very low at wide-angle and telephoto.

Corner Softness. At full wide-angle, our copy of the 18-55mm lens was quite soft on the right-hand side, and the softness extended pretty far into the frame. The left side wasn't nearly as soft, with only minor to moderate blurring in the extreme corners. The center of the image was sharp with good contrast. Some vignetting (corner shading) is also noticeable at full wide-angle. At full telephoto, the ride side again was softest, but not nearly as soft as wide-angle. The corners in the left hand-side were quite sharp, and the center was also sharp, but the lens had lower contrast overall at full telephoto. A slightly below average performance overall for a kit lens here. (Note that the lens was "wide-open" for these shots, and corner sharpness generally improves when a lens is "stopped-down" a couple of f-stops below full aperture.)

The Sony A33 doesn't appear to be applying any chromatic aberration in its JPEGs, as uncorrected RAW files show similar amounts. 

Internal Mirror Reflections

When additional surfaces are added to an optical path, especially ones not parallel with the image plane, there is always a chance that light will travel an unintended path. In the case of the A33 and A55V, it appears that the rear surface of the translucent mirror film can reflect light back to the front surface of the film, which reflects it back to the rear, causing a "ghost" reflection or multiple reflections to appear in the final image under certain conditions. The above left crop shows this phenomenon in one of our Sony A33 flash test shots, where a very strong reflection from the plastic edging of our flash-range/uniformity target also has a small ghost image in the form of a horizontal white line below it. (Thanks to IR reader Erick E for pointing this out in one of our A55 flash range images!) The crop on the right is from a similar flash shot, taken with the same lens, but using the Sony A560 which is a traditional SLR without a translucent mirror in the optical path. As you can see, under nearly identical conditions (the A560's flash is a bit stronger), no ghosting is present.

We only found ghosting in a small subset of our test images, as it seems to require fairly specific conditions to be noticeable. Ghosts only appear in a couple of our flash shots similar to the one shown above, as it appears that camera/subject angle needed to be just right, to reflect enough light from the flash head back into the lens to show the ghost. Dave also saw this phenomenon in some night shots he has taken with the Sony A55V, which we hope to share some crops from shortly. From Dave's experience, the ghosting seems to require a very concentrated light source, sharply focused, and ideally a relatively small light source with darker areas surrounding it. The ghosting did not appear with larger, less sharply-defined light sources, or when light spilled from the source on surrounding areas (thereby making the lighting broader and more diffuse). Under conditions of really severe light overloads ghosts seem to be masked by lens flare. Based on our tests, we can confirm that this is a genuine phenomena with the Sony A33/55. Should you be concerned about it? Perhaps. Some people would certainly find it objectionable, especially if they did a lot of night photography of things like cityscapes. Personally, it wouldn't deter us from buying a Sony A33, because we don't do much cityscape-type photography: Our night shots tend to be ones where the subjects are people or areas lit by nearby light sources. With these sorts of shots, ghosting of the type shown above wouldn't be an issue. Bottom line, you'll need to decide for yourself if this would impact your personal style of shooting enough to outweigh the benefits of the Sony A33's pellicle mirror design.

The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Sony Alpha SLT-A33 Photo Gallery .

Exposure

Sony Alpha A33 Exposure Options

The Sony A33 offers much the same exposure options you'd find in a traditional SLR camera, plus a few Sony-specific options. Available exposure modes include Program AE, Manual, Aperture Priority, and Shutter Priority modes, with shutter speeds from 1/4,000 to 30 seconds, as well as a Bulb setting for longer exposures. The x-sync speed for flash photography is 1/160 second. A fully automatic mode called Auto+ enables Scene Detection, and places the camera in control of almost all functions, to try to deliver optimum results under a wide range of conditions. Basic options such as exposure compensation aren't available to the photographer in this mode, and the A33 can even automatically enable multiple-exposure modes that capture a burst of images. The Sony A33 also offers a number of Scene modes, a Sweep Panorama mode, and a Multi Frame NR mode which merges multiple images into a single exposure with reduced noise. See the Modes and Menus page for more details.

The A33 offers an optional live histogram function in all operating modes except Sweep Panorama. Located near the bottom right corner of the LCD panel, it's rather small, and offers only a luminance readout rather than a full RGBY histogram, but it's still very useful for ensuring your exposures are correct. Another feature that's rather more common, but still very welcome, is the exposure display visible near the bottom right of the LCD when the camera is in Manual exposure mode. This shows the amount the camera thinks an image will be over- or underexposed within a range of +/-2.0EV, based on the settings you have selected, to help you find the best exposure for the subject. (Beyond the 2.0EV range, arrows on either end of the scale blink to emphasise that the metering system's limit has been reached.) Together, the live histogram and exposure display make it relatively easy to get suitable exposures even when shooting manually.

Sony A33 Face Detection
The Sony A33 includes Face Detection capability, capable of locating up to eight faces in the scene simultaneously. This information is taken into account when determining several exposure variables -- focus, exposure, flash and white balance. The A33 doesn't go as far as some cameras that try to recognize specific individuals, nor is it able to differentiate between adult and child faces. It does, however, includes a related feature that is now pretty common in point-and-shoot cameras, but relatively unknown in large-sensor cameras. Dubbed "Smile Shutter", this allows the A33 to automatically trigger the shutter, capturing photographs by itself when a smiling face is detected within the image frame. The A33's implementation is perhaps best suited to portraits of individuals, since the shutter is tripped when only one face within a group is smiling. There's a three-step control over the degree to which a subject must smile before the shutter is tripped. and when Smile Shutter is enabled, the A33 also provides a graph at the left of the screen that indicates how close a particular expression has come to passing the required threshold for the shutter to be tripped. In our testing we found the feature a little hit-and-miss, however, consistently spiking to the top of the scale and tripping the shutter for some individuals with barely the slightest smile, even when set to require a big smile.

Sony A33 ISO Range
ISO sensitivity ranges from 100 to 12,800, a wider range than that offered by many recent traditional SLRs. The ISO sensitivity is adjusted through the Function menu, or by pressing the ISO (Down Arrow) button on the four-way controller, and adjustments can be made in one-stop increments.

In all but Manual mode, an Auto ISO mode is available. The function is limited to a maximum of ISO 1,600 in most operating modes, although the Hand-held Twilight mode will allow Auto ISO to range as high as ISO 6,400 equivalent if needed.

In addition, the Sony A33 offers a Multi-Frame NR mode, which couples multiple shots into a single output image, in a similar manner to the Hand-held Twilight mode, but allows direct control over ISO sensitivity. When using Multi-Frame NR, the maximum ISO sensitivity limit is expanded to ISO 25,600 equivalent.

Sony A33 Noise Reduction
The Sony A33 gives you only two choices for High ISO noise reduction, neither of which allows the function to be completely disabled. The default is to leave High ISO NR entirely in the camera's control, but if the maximum image detail is desired (or you prefer to do your noise filtering in post processing), a "Weak" option is also available in all except Auto, Auto+, Sweep Panorama, or Scene modes. The Auto option cannot be selected in continuous shooting or bracketed image bursts.

A separate Long Shutter noise reduction On / Off setting is available for dark frame subtraction when shooting exposures of one second or longer. If enabled, this approximately doubles the exposure time for each shot, allowing the second dark frame exposure to be captured with the shutter closed. Long Exposure NR can't be disabled in Auto+, Auto, or Scene modes, and cannot be enabled for Multi-Frame NR, Sweep Panorama, Hand-Held Twilight, Continuous / Advance Priority Continuous, or Bracketed shooting.

Sony A33 White Balance Options
White balance modes on the Sony A33 include Auto, Daylight, Shade, Cloudy, Incandescent, Fluorescent, and Flash. A direct Kelvin temperature setting is also available, ranging from 2,500K to 9,900K, as is a Custom white balance setting, for setting white balance from a white or grey card. The A33's popup flash strobe can be used when determining a custom white balance, and unusually, the camera also provides a Kelvin readout of the measured color temperature -- a great feature which lets you dial the temperature in directly if you're shooting in familiar conditions. The effect of changes in white balance settings is shown in real-time, on the LCD monitor or EVF.

In all of the preset white balance modes, you can fine-tune the color by pressing the left / right arrow keys on the four-way controller while in the White Balance menu. Blue / red adjustment within a range of -3 to +3 arbitrary units for all but the fluorescent mode, which offers only a -1 to +2 unit range. In Kelvin white balance mode, there's also a color filter function which offers a magenta - green filter within a fairly wide range of -9 to +9 arbitrary units.

Custom white balance is set by selecting Custom Setup from the white balance menu, and pointing the camera at a neutral white or grey card under the lighting you'll be shooting in, filling a frame in the center of the display with the reference target, then pressing the Shutter button.

In addition, the Sony A33 can bracket white balance using the White Balance Bracketing (BRK WB) option in the Drive Mode menu. For each shutter release, the A33 records three separate image files, varying only the white balance between each image. Two step sizes are available -- 10 mireds when using the BRK WB Lo setting, and 20 mired steps with the BRK WB Hi setting.

Sony A33 Metering Options
The Sony Alpha A33 offers three metering modes, selected via the Metering Mode option in the Function menu: Multi-pattern, Center-Weighted, and Spot. All three modes operate on data from the camera's CMOS image sensor. The default Multi-segment metering mode divides the image into 1,200 segments, and compares these to determine exposure. Center-Weighted gives precedence to the center of the image while reading the whole frame. Spot metering is useful for high-contrast subjects, as it bases the exposure reading on the very center of the image, letting you set the exposure based on a small portion of your subject. When the camera is operating in Auto+, Auto, or Scene modes, the metering mode is fixed to Multi-pattern, and cannot be changed.

By default, you can lock an exposure reading separately from autofocus lock by pressing and holding the AEL button. Alternatively, the AEL button behaviour can be changed so that pressing and releasing the button will set and release the autoexposure lock on subsequent presses.

Sony A33 Exposure Compensation & Bracketing
The Sony A33's Exposure Compensation adjustment increases or reduces the overall exposure from -2 to +2 exposure values (EV) in one-third stop increments, and like White Balance, the effect of Exposure Compensation is simulated on the preview. In addition, the A33 offers -2 to +2 EV of flash exposure compensation, in 1/3 EV increments, set through the Function menu. A Continuous Bracketing feature captures multiple shots with different exposures. See the Drive Mode section on Continuous Bracketing below for more details.

Sony A33 DRO / HDR
The Sony A33 offers two different functions aimed at handling high-contrast scenes, each functioning in a rather different manner. The Dynamic Range Optimization (DRO) function adjusts the tone curve of captured images, bringing out shadow detail without adversely affecting highlights. As well as an Auto DRO mode, there are also five different levels of DRO available. Alternatively, Sony has included a high dynamic range (HDR) mode, which captures three separate images with varied exposures, and then combines the images in-camera, creating a single image with significantly increased dynamic range. The A33 can either automatically select the exposure variation, or a value can be selected manually in 1EV steps within a range of 1EV to 6EV.

The DRO and HDR modes can't be used together, and each brings its own set of advantages and disadvantages. Since DRO only works from a single shot, it must operate entirely within the dynamic range available from the image sensor, where the HDR mode is able to capture a significantly greater dynamic range than is possible in one shot. Since DRO is effectively amplifying the signal in shadow areas of the image, it also brings increased noise (or increased noise reduction) in the shadows. HDR mode, meanwhile, is suitable only for relatively static subjects, given that it requires multiple exposures. Thanks to microalignment capability, Sony's HDR mode is at least able to deal with the slight changes in framing caused by shooting handheld, but subject motion or camera shake will likely cause unacceptable artifacts in HDR images.

Both DRO and HDR can be disabled altogether if desired, although the default on the A33 is for DRO Auto mode to be left enabled.

Sony A33 Hand-held Twilight
Another function which the Sony A33 has inherited from the company's point-and-shoot camera line is its Hand-held Twilight mode, which is accessed from the Scene (SCN) position on the Mode dial. Hand-held Twilight mode shoots a burst of six images with a single press of the shutter button, using as high sensitivity as is necessary to offer hand-holdable shutter speeds. The A33 then combines all six source images into one image with reduced noise in static areas, as compared to a single shot taken with the same exposure settings. Cleverly, Hand-held Twilight mode is able to deal with moving subjects, by making the assumption that the first frame includes your intended subject. Areas of subsequent images which match up with the first image are factored into the final result, but areas that don't match -- either due to subject or camera motion -- aren't used in creating the final image. This does, however, mean that the moving subject doesn't benefit from the same degree of noise reduction as the rest of the image.

The Sony A33's implementation of Hand-held Twilight does have one important difference from the similar mode found on its point-and-shoot siblings. Where the existing cameras have been able to use an electronic shutter to capture the source images, the A33 must instead rely on its physical shutter. The act of firing the A33's shutter is surprisingly loud, given that there's no reflex mirror entering into the equation -- we've seen some DSLRs issuing similar noise levels (or possibly even a little less). The net result is that with six frames captured in a rapid burst, the A33's Anti-Motion Blur mode can have bystanders turning around in expectation of seeing a paparazzo in their midst. ;-)

Sony A33 Multi-Frame NR
Another function that's closely related to Hand-held Twilight is Sony's Multi-Frame NR mode. A new addition for Sony's SLT-series cameras, Multi-Frame NR has several important differences. Most significantly, it functions in the A33's Program, Aperture- or Shutter-Priority, and Manual modes. In all but Manual mode, it offers the ability to let the camera choose the sensitivity automatically, but unlike Hand-held Twilight it also allows manual selection of ISO sensitivity (and indeed, for Manual exposure shooting, that's the only option given.) One further difference of note is that in Multi-frame NR mode, the maximum ISO sensitivity limit of the Sony A33 is raised from its standard ISO 12,800 equivalent, to an impressively high 25,600 equivalent.

Sony A33 Sweep Panorama
The final mode inherited from Sony's Cyber-shot point-and-shoot lineup is the A33's Sweep Panorama function, with which it can automatically capture a burst of images, and stitch them into a single panoramic image in-camera. Both 2D and 3D modes are offered, with the latter cleverly comparing the relative positions of subjects as they pass the left and right sides of the lens, and using this information to create a 3D image consisting of separate 2D views, stored in a Multi Picture Object file.

Again, since there's no electronic shutter to rely on, the focal plane shutter noise means you won't be catching anybody by surprise, That said, the feature functions pretty well if you've a reasonably steady hand, and your subject matter isn't too close to the camera. If your subject matter is too close to the camera, or your panning isn't smooth and straight, the seams between separate images can become fairly noticeable. Focus and exposure are locked from the first frame of the panorama, so you'll want to pick your starting point carefully. From there, you can pan left, right, up, or down, simply sweeping the camera across your subject matter after pressing the shutter button.

Two panorama sizes are available -- standard, or wide. Standard horizontal panoramas are limited to 15 megapixels, and vertical panoramas to 8.4 megapixels. In Wide mode, horizontal panoramas are 23 megapixels, and vertical panoramas are 12 megapixels. For 3D mode, only horizontal panoramas are possible, with the standard size providing 5.3 megapixel resolution, and the wide size offering 7.7 megapixels. There's also a 1,920 x 1,080 pixel mode designed to match the resolution of a Full HD display, available only for 3D panoramas.

A darkened mask over the left third of the LCD display shows an area of the frame that won't be included in the final output image, and an on-screen message warns you if the Alpha A33 wasn't able to track your panning, prompting you to recapture the panorama. (Depending on how much was captured, the A33 sometimes retains a partial panorama with the uncaptured portion of the image left as a flat grey.)

Sony A33 Drive Modes
The Sony A33 offers a variety of shooting modes through the Drive Mode option under the Function menu, which can also be accessed by pressing the left-arrow button in all shooting modes except Continuous Advance Priority, Sweep Panorama, and Hand-held Twilight modes. Drive options vary depending on the shooting mode, but include Single Shot Advance, two Continuous Advance modes, two Self Timer modes, Continuous Bracket, White Balance Bracket, and Remote Commander. Single-shot, as you'd expect, captures a single image with each press of the shutter button. Continuous Advance captures images at either six frames per second in Hi mode, or 2.5 frames per second in Lo mode, while the shutter button is held down. As many as 7 RAW or 14 Large / Fine JPEG shots can be captured in a burst, adjusting focus and exposure between shots as necessary. The Self-timer modes offers a choice of either two or ten second timers. Continuous Bracket mode lets you take a sequence of three shots with either 0.3 EV or 0.7 EV exposure variation steps, with the sequence order being to shoot the metered exposure first, followed by the underexposed and overexposed frames. White Balance Bracket captures three images with varied white balance settings, as described in the white balance section of this page. Finally, Remote Commander mode configures the A33 to capture images as directed by the optional RMT-DSLR1 wireless remote control, which communicates with the camera via an infrared receiver located in the top of the hand grip.

The Sony A33 also offers a separate Continuous Advance Priority mode, accessed from its own position on the Mode dial. When enabled, this boosts the frame rate significantly to a whopping seven frames per second, and allows both autofocus and autoexposure to continue to operate between frames. There's an important proviso to note if using Continuous Autofocus, though. To allow sufficient light to reach the camera's phase detection autofocus sensor without the need to adjust the lens aperture between frames, the Continuous Advance Priority mode locks the aperture at or near its open position, reducing the available depth of field. The only way to avoid this requirement is to use either single autofocus, or manual focus. With single autofocus, the focus point is locked from the first frame.

Sony A33 Creative Styles
Finally, the Creative Style option on the Function menu allows photographers to set the A33's color mode. Six preset options are available -- Standard, Vivid, Portrait, Landscape, Sunset, and B/W. For all six choices, Contrast and Sharpness levels may be adjusted in seven steps. In addition, all but the black and white mode offer seven-step control over saturation. A separate Color Space option under Screen 2 of the Record menu lets you choose between sRGB and AdobeRGB color spaces, with sRGB being best for viewing images on a computer, and Adobe RGB the best choice for printing images.

The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Sony Alpha SLT-A33 Photo Gallery .

Not sure which camera to buy? Let your eyes be the ultimate judge! Visit our Comparometer(tm) to compare images from the Sony Alpha SLT-A33 with those from other cameras you may be considering. The proof is in the pictures, so let your own eyes decide which you like best!

Performance

Sony A33 Performance

Imaging

Sony A33 Image Quality

Color

Saturation & Hue Accuracy
Very good overall accuracy and saturation, with only minor shifts in hue and intensity.

In the diagram above, the squares show the original color, and the circles show the color that the camera captured. More saturated colors are located toward the periphery of the graph. Hue changes as you travel around the center. Thus, hue-accurate, highly saturated colors appear as lines radiating from the center. Click for a larger image.

Saturation. The Sony A33 pushes strong reds, dark blues and some greens and browns just a little, but actually undersaturates bright yellow, light green, aqua, and cyan tones slightly. The A33's overall color saturation is about average for a consumer oriented camera. You can of course tweak saturation to your liking, or choose a different color mode. See the comparison of available "Creative Style" image options below. Most consumer digital cameras produce color that's more highly saturated (more intense) than found in the original subjects. This is simply because most people like their color a bit brighter than life.

Skin tones. Here, when adjusted for the correct white balance, the Sony A33 did well, producing natural-looking skin tones. Where oversaturation is most problematic is on Caucasian skin tones, as it's very easy for these "memory colors" to be seen as too bright, too pink, too yellow, etc.

Hue. The Sony A33 did push cyan toward blue, red toward orange, orange toward yellow and yellow toward green, but shifts were relatively minor. (The cyan to blue shift is very common among the digital cameras we test; we think it's a deliberate choice by camera engineers to produce better-looking sky colors.) With an average "delta-C" color error of only 4.53 after correction for saturation, overall hue accuracy was very good; much better than average. Hue is "what color" the color is.

Creative Style
The Sony A33 offers six preset "Creative Style" options. You can adjust contrast, saturation, and sharpness for any of the settings.

Creative Style Options
Standard	B&W	Landscape
Portrait	Sunset	Vivid

Mouse over the links above to see the effect of the presets on our Still Life target. Click on a link to load the full resolution image.

Saturation Adjustment
The Sony A33 has a total of seven saturation settings available, three above and three below the default saturation. This covers a pretty wide range of saturation levels, about as wide a range as you're likely to find photographically relevant, apart from special effects that are arguably better achieved in software. The fine steps between settings mean you can program the camera to just the level of saturation you prefer, a feature we look for in cameras.

Saturation Adjustment Examples
-3	-1	0	+1	+3

The table above shows results with five of the seven saturation settings, including the default and the two extremes. Click on any thumbnail above, then click again to see the full-sized image.

Sensor

Exposure and White Balance

Indoors, incandescent lighting
Very warm cast with Auto, but good color with the Incandescent and Manual settings. About average amount of positive exposure compensation required.

Indoors, under normal incandescent lighting, color balance was overly warm with the Auto white balance setting. Results with the Incandescent setting were quite good, just slightly warm. The Manual setting was very accurate, though some may prefer Incandescent because it conveys a touch more of the warmth of the original lighting. The 2,600 Kelvin setting which matches the color temperature of our lights resulted in a slightly cool, bluish image. The Sony A33 required +0.3 EV positive exposure compensation here, which is average for this shot. (Our test lighting for this shot is a mixture of 60 and 100 watt household incandescent bulbs, a pretty yellow light source, but a very common one in typical home settings here in the U.S.)

Outdoors, daylight
Very good results under harsh lighting, with good handling of contrast, detail, and exposure.

Manual White Balance, Auto Exposure	Auto White Balance, Auto Exposure

Outdoors, the Sony A33 performed well, requiring no exposure compensation to keep the model's face bright in our "Sunlit" Portrait shot. The average among the cameras we've tested is +0.7 EV, so the A33 performed better than average here. Contrast is a little high, as you might expect under such harsh lighting, but the camera does a good job of holding onto detail in both the deep shadows and bright highlights, without the help of DRO (DRO was off for these shots). Despite the apparent brightness, there are very few clipped highlights in the model's face and shirt, with most of the clipping occurring in specific color channels in the flowers. There weren't many lost shadows either. Only a few highlights were blown in the House shot at the default exposure as well, also a very good result. Color balance is good, though Auto white balance rendered the model's face a touch too cool. We preferred results from the Manual white balance setting. The Far-field House shot had very good color, also just a touch cool. Overall, very good performance.

See full set of test images with explanations
See thumbnails of all test and gallery images

Resolution
Very high resolution, 1,900 ~ 2,100 lines of strong detail.

In camera JPEGs of our laboratory resolution chart revealed sharp, distinct line patterns down to about 2,100 lines per picture height in the horizontal direction, and about 1,900 lines per picture height in the vertical direction. Complete extinction of the pattern didn't occur until about 2,600 to 2,800 lines. Use these numbers to compare with other cameras of similar resolution, or use them to see just what higher resolution can mean in terms of potential detail.

See full set of test images with explanations
See thumbnails of all test and gallery images

Sharpness & Detail
Very good detail and sharpness, with some minor edge-enhancement on high-contrast subjects. Moderately low noise suppression visible in the shadows and areas of low contrast.

Very good definition of high-contrast elements with some visible sharpening artifacts.	Subtle detail: Hair Noise suppression tends to blur detail in areas of subtle contrast.

Sharpness. The Sony A33 captures fairly sharp, detailed images overall when using a sharp lens (the above left crop is from a shot taken with the very sharp Carl Zeiss Vario-Sonnar T* 24-70mm F2.8 lens), though some edge enhancement artifacts are visible on high-contrast subjects such as the tree branches, roof and trim in the crop above left. Fine detail such as the smaller branches and pine needles show very little edge enhancement. The A33 offers seven levels of sharpening though, so you can always tweak JPEG output to your taste. Edge enhancement creates the illusion of sharpness by enhancing colors and tones right at the edge of a rapid transition in color or tone.

Detail. The crop above right shows moderately low noise suppression in the darkest areas of the model's hair. Some individual strands are smudged together, though quite a few strands are still visible despite the low contrast subject. Overall, very good results here for a 14-megapixel APS-C sensor. Noise-suppression systems in digital cameras tend to flatten-out detail in areas of subtle contrast. The effects can often be seen in shots of human hair, where the individual strands are lost and an almost "watercolor" look appears.

RAW vs In-Camera JPEGs
As noted above, the Sony A33 produces fairly sharp, detailed in-camera JPEGs. However, quite a bit more detail can often be obtained from carefully processing RAW files with a good RAW converter.

Fine Camera JPEG (Default settings)	RAW via Sony IDC (Default settings)	RAW via Sony IDC (Sharpening = 100)	RAW via ACR, then sharpened in Photoshop

In the table above, mousing over a link at the bottom will load the corresponding crop in the area above, and clicking on the link will load the full resolution image. Examples include (from left to right): an in-camera Fine JPEG, RAW file processed through Sony's Image Data Converter SR version 3.2 software at default settings, another processed with IDC's sharpening turned up to +100, and finally one converted with Adobe Camera RAW 6.2, sharpened in Photoshop. For the Sony A33's images, I found best results with strong but tight 300% unsharp masking with an 0.3 pixel radius.

As you can see, the Sony IDC version at default settings is somewhat softer than the in-camera JPEG. (Color rendering is also slightly different.) Increasing the sharpness helped, but the resulting image doesn't really show any additional detail. There is also an odd green coloration along some of the white trim on the house that's not present in the camera JPEG, so it's possible IDC still needs some work to properly support the Sony A33's ARW files. On the other hand, the Adobe Camera RAW version sharpened in Photoshop reveals quite a bit more fine detail.

ISO & Noise Performance
Very good noise performance for a 14-megapixel APS-C sensor, with excellent results up to ISO 800.

Default High ISO Noise Reduction
ISO 100	ISO 200	ISO 400
ISO 800	ISO 1,600	ISO 3,200
ISO 6,400	ISO 12,800

The Sony A33's images are quite clean at ISO 100 and 200, and ISO 400 is almost as good. Some noise "grain" is noticeable at ISO 800, and there's a bit of chroma noise in the shadows, but the camera doesn't smudge away as much fine detail as most others at this ISO. There's some stronger smudging of fine detail at ISO 1,600, but the A33 still does better than most at this ISO for its resolution. At ISO 3,200, fine detail suffers from more aggressive noise reduction, but there is still some detail left, though chroma noise is starting to become an issue in the shadows. Detail takes larger hit at ISO 6,400 and especially 12,800. There's also quite a bit of chroma noise in the form of purple and yellow blotching, especially at ISO 12,800. Overall though, these are very good results, but not quite as good as those from the Sony NEX-3 and NEX-5 which likely share the same or very similar sensor. As always, see the Print Quality section below for maximum recommended print sizes at each ISO.

A note about focus for this shot: We shoot this image at f/4, usually using one of three very sharp reference lenses (70mm Sigma f/2.8 macro for most cameras, 60mm f/2.8 Nikkor macro for Nikon bodies without a drive motor, and Olympus Zuiko 50mm f/2.0 for Four Thirds and Micro Four Thirds bodies). To insure that the hair detail we use for making critical judgements about camera noise processing and detail rendering is in sharp focus at the relatively wide aperture we're shooting at, the focus target at the center of the scene is on a movable stand. This lets us compensate for front- or back-focus by different camera bodies, even those that lack micro-focus adjustments. This does mean, though, that the focus target itself may appear soft or slightly out of focus for bodies that front- or back-focused with the reference lens. We know this; if you click to view the full-size image for one of these shots and notice that the focus target is fuzzy, you don't need to email and tell us. :-) The focus target position will have been adjusted to insure that the rest of the scene is focused properly.

Noise Reduction Oddity. The "Weak" high ISO NR setting smudges the red leave pattern in our Still Life target setting more than the "Auto" setting at higher ISOs. The Auto setting does reduce chroma noise compared to the Weak setting though (lower crops). We saw similar behavior with previous Sony models such as the NEX-5/3 and A550/A500.

Extremes: Sunlit and low light tests
Very high resolution with excellent highlight and shadow detail. Very good low-light performance, capable of capturing bright images in near darkness. Special modes make it possible to capture low-light images without a tripod.

Sunlight. The Sony A33 handled the deliberately harsh lighting in the test above very well. Though contrast is a little high, shadow and highlight detail are both very good. The camera's contrast adjustment also did a good job of decreasing overall contrast without producing strong color variations; see the section below. The default exposure (0 EV) did the best job here, as the model's face was reasonably well exposed without blowing as many highlights as the +0.3 and +0.7 EV settings. Note that these shots were captured with the Sony A33's DRO (Dynamic Range Optimizer) control set to Off, so the camera's dynamic range is pretty good even without the aid of DRO. Still, be sure to use fill flash in situations like the one shown above; it's better to shoot in the shade when possible. See below for DRO results.

Because digital cameras are more like slide film than negative film (in that they tend to have a more limited tonal range), we test them in the harshest situations to see how they handle scenes with bright highlights and dark shadows, as well as what kind of sensitivity they have in low light. The shot above is designed to mimic the very harsh, contrasty effect of direct noonday sunlight, a very tough challenge for most digital cameras. (You can read details of this test here. In actual shooting conditions, be sure to use fill flash in situations like the one shown here; it's better to shoot in open shade whenever possible.)

Contrast Adjustment
We really like it when a camera gives us the ability to adjust contrast and saturation to our liking. It's even better when those adjustments cover a useful range, in steps small enough to allow for precise tweaks. Just as with its saturation adjustment, the Sony A33's contrast setting meets both challenges.

Minimum Contrast
Contrast set to lowest, Auto Exposure	Contrast set to lowest, Auto Exposure

At its lowest contrast setting, the A33 did a really excellent job of preserving highlight detail, maintaining natural-looking skin tones, and holding nice detail in the shadows. The Sony A33 captures good color outdoors, though just a touch on the cool side. Overall, very good results here, especially when the contrast setting is tweaked. (This is a really tough shot; the Sony does a much better than average job handling it.)

Contrast Adjustment Examples
-3	-1	0	+1	+3

The table above shows five of the seven contrast setting, including the default and two extremes. It's pretty hard to evaluate small differences in contrast on small thumbnails like these, so click on any thumbnail to go to the full-size image.

One very nice feature of Sony's contrast adjustment is that it has very little effect on color saturation. Contrast and saturation are actually fairly closely coupled, it's a good trick to be able to vary one with out the other changing as well. Sony did a good job here.

Outdoor Portrait DRO Examples
DRO Off	DRO Auto	DRO Level 1	DRO Level 5
Highlights
Shadows (Levels adjusted equally in Photoshop on the right-hand side to show noise)

Dynamic Range Optimization is Sony's name for their dynamic range enhancement technology. DRO divides the image into small areas, analyzes the range of brightness of each area, and adjusts the camera's image processing parameters accordingly to make the best use of the available dynamic range. The Sony A33 enables Auto DRO by default. You can also set the level manually, from 1 ("weak") to 5 ("strong"). As one would expect, DRO is only available for JPEGs.

The above images and crops show the effects of DRO disabled, set to Auto (the default), Level 1 ("weak") and Level 5 ("strong") for our "Sunlit" Portrait shot. As you can from the crops, Auto DRO had very little effect on the highlights in this shot, as the images are virtually the same when it comes to highlights. This is because very few highlights were lost in the first place. (Despite the apparent brightness, almost no highlights were clipped in the white shirt.) The bulk of the difference between different levels of DRO is found in the shadow areas. The stronger the level, the more boost is applied to the shadows. Along with that boost is an increase in shadow noise, though noise is not as much of an issue as we expected for a 14-megapixel subframe sensor.

Far Field DRO Auto Example
DRO Off, 0 EV	DRO Auto, 0 EV
Highlights
Shadows

Here's an example of Auto DRO at work with our Far-field House shot. The difference is very subtle, with just a slight boost to the shadows.

Far Field DRO Levels
Level 1	Level 2	Level 3
Level 4	Level 5	Auto

Above, you can see the effects of the five manual levels of DRO, plus Auto, on our Far-field House shot. Auto DRO produced results similar to the manual Level 1 setting, though not identical.

Outdoor Portrait HDR Examples
HDR Off	HDR Auto	HDR 1 EV	HDR 6 EV
Highlights
Shadows (Levels adjusted equally in Photoshop on the right-hand side to show noise)

High Dynamic Range. The Sony A33's HDR mode takes three images in rapid succession, one at the nominal exposure, one underexposed, and one overexposed, then combines them into one high dynamic range JPEG automatically. Highlight areas from the underexposed image, shadow areas of the overexposed image, and properly exposed areas from the nominal image are combined in-camera to produce an image with increased dynamic range. The camera saves the composite image, as well as the one taken at nominal exposure. The overlaid images are micro-aligned by the camera, but it can only correct for so much movement. If it can't micro-align successfully, an icon indicating HDR capture failed will appear. The user manual warns that for best results, the subject should not move or blink, so it's not really intended for portraits. There is also a manual mode where you can select 1 EV ("weak") to 6 EV ("strong") difference in exposures. As you can see, the Auto setting produced an image that looks quite flat and unnatural, roughly matching the 3 EV setting. The lowest manual setting of 1 EV did a great job however, taming highlights and boosting shadows without additional noise. In fact, shadow noise is lower since the overexposed image would have less noise in the shadows than the nominally exposed image. There may also be some blending going on, which would also average out random noise. 

Far Field HDR Example
HDR Off, 0 EV	HDR Auto, 0 EV
Highlights
Shadows

Above is another example of the Sony A33's HDR mode at work. As you can see, both highlights and shadows are well preserved, with no noise penalty. The image does look a bit flat, though. If you look carefully at the full resolution HDR image, you will see some ghosting in the leaves, caused by movement from wind during the exposures.

Far Field HDR Levels
1 EV	2 EV	3 EV
4 EV	5 EV	6 EV
	Auto

Above, you can see the effects of the six manual levels of HDR on our Far-field House shot, plus Auto. Auto HDR produced results similar to the manual 2 EV setting, though not identical.

Because digital cameras are more like slide film than negative film (in that they tend to have a more limited tonal range), we test them in the harshest situations to see how they handle scenes with bright highlights and dark shadows, as well as what kind of sensitivity they have in low light. The shot above is designed to mimic the very harsh, contrasty effect of direct noonday sunlight, a very tough challenge for most digital cameras. (You can read details of this test here.)

	1 fc 11 lux	1/2 fc 5.5 lux	1/4 fc 2.7 lux	1/8 fc 1.3 lux	1/16 fc 0.67 lux	1/16fc No NR	1/16fc MF NR
ISO 100	2 sec f2.8	4 sec f2.8	8 sec f2.8	15 sec f2.8	30 sec f2.8	30 sec f2.8	13 sec f2.8
ISO 200	1 sec f2.8	2 sec f2.8	4 sec f2.8	8 sec f2.8	15 sec f2.8	15 sec f2.8	6 sec f2.8
ISO 400	0.5 sec f2.8	1 sec f2.8	2 sec f2.8	4 sec f2.8	8 sec f2.8	8 sec f2.8	3.2 sec f2.8
ISO 800	1/4 sec f2.8	0.5 sec f2.8	1 sec f2.8	2 sec f2.8	4 sec f2.8	4 sec f2.8	1.6 sec f2.8
ISO 1600	1/8 sec f2.8	1/4 sec f2.8	0.5 sec f2.8	1 sec f2.8	2 sec f2.8	2 sec f2.8	0.8 sec f2.8
ISO 3200	1/15 sec f2.8	1/8 sec f2.8	1/4 sec f2.8	0.5 sec f2.8	1 sec f2.8	1 sec f2.8	0.4 sec f2.8
ISO 6400	1/30 sec f2.8	1/15 sec f2.8	1/8 sec f2.8	1/4 sec f2.8	0.5 sec f2.8	0.5 sec f2.8	1/5 sec f2.8
ISO 12800	1/60 sec f2.8	1/30 sec f2.8	1/15 sec f2.8	1/8 sec f2.8	1/4 sec f2.8	1/4 sec f2.8	1/10 sec f2.8
ISO 25600	n/a	n/a	n/a	n/a	n/a	n/a	1/20 sec f2.8

Low light. The Sony A33 performed well in our low light test, producing bright images down to the lowest light level we test at (1/16 fc) at all ISO settings. The metering system struggled a bit at very low light levels though, so we used manual exposure for these shots (except for the Multi-frame NR examples in right-most column, which used Aperture-priority). Noise is very well controlled up to ISO 800, though as expected, at higher ISOs there are moderate to high amounts of fine luminance noise and some blotchy chroma noise. Auto white balance did a very good job here, producing a neutral color balance at all ISOs and light levels. There is just a hint of some horizontal banding at very high ISOs, but that's not uncommon. Hot pixels can be seen with long exposure noise reduction turned off (the second column from he right), even at ISO 100, but they are few and far between. The right-most column shows the results with Multi-frame Noise Reduction active. It really does a good job at reducing noise compared to a single frame at the same ISO and light level, though that's a little hard to tell from these shots, because the Sony A33's metering system underexposed them.

The camera's autofocus system was able to focus on the subject down to below the 1/16 foot-candle light level unassisted with the 18-55mm kit lens. That's excellent performance even for an SLR. The SLT-A33 was able to focus in complete darkness with its built-in focus assist lamp enabled.

How bright is this? The one foot-candle light level that this test begins at roughly corresponds to the brightness of typical city street-lighting at night. Cameras performing well at that level should be able to snap good-looking photos of street-lit scenes.

NOTE: This low light test is conducted with a stationary subject, and the camera mounted on a sturdy tripod. Most digital cameras will fail miserably when faced with a moving subject in dim lighting. (For example, a child's ballet recital or a holiday pageant in a gymnasium.) Thanks to their phase-detect AF systems, digital SLRs like the Sony A33 tend to do much better than point & shoots, but you still shouldn't expect a quick autofocus lock with moving subjects. (A useful trick is to just prop the camera on a convenient surface, and use its self-timer to release the shutter. This avoids any jiggling from your finger pressing the shutter button, and can work quite well when you don't have a tripod handy.)

Low Light Hand-Held Twilight
Manual, 1/30s, ISO 6400	Hand-Held Twilight, 1/60s, ISO 6400
Detail
Noise

Hand-Held Twilight. A feature inherited from Sony's Cyber-shot point-and-shoot cameras, Hand-held Twilight mode shoots a burst of six images with a single press of the shutter button, using high enough sensitivity to hand-hold the camera in fairly low light. The A33 then combines all six source images into one image with reduced noise in static areas, as compared to a single shot taken with the equivalent exposure settings. In the example above, Hand-Held Twilight mode chose ISO 6,400 at a shutter speed of 1/60s. As you can see, the camera managed to get an image almost as sharp with similar noise while being hand-held (on right) as with the same ISO on a sturdy tripod, though the resulting image in this case is a bit dim. (We found this feature works better on real-world subjects such as poorly lit nightscapes.)

Low Light Multi-frame NR
Manual, 1/4s, ISO 12800	Multi-frame NR, 1/10s, ISO 12800
Detail
Noise

Multi-frame Noise Reduction. This new feature is similar to Hand-held Twilight mode, but gives you control over the ISO used, so you may still need to use a tripod depending on the ISO you select. (We frankly don't see the value to this mode when using a tripod, as selecting a lower ISO and longer shutter speed will produce a clean image as well.) As you can see, the image captured with Multi-frame Noise Reduction (right) is cleaner than the standard image (left) despite both being shot at ISO 12,800, though the underexposure isn't really showing what the technique is capable of. An added bonus is that ISO 25,600 equivalent is available with MF NR.

Here's a better example of Multi-frame Noise Reduction at work using our Still Life target in good light at ISO 6,400:

Multi-frame NR
Normal mode, 1/1250s, ISO 6400	Multi-frame NR, 1/1250s, ISO 6400

Output Quality

Print Quality

Print quality is very impressive, producing usable prints from every ISO setting.

The Sony A33's ISO 100 images look great printed at 20x30 inches, and could probably even go higher. All of these prints, by the way, were made with the default Auto Noise Reduction settings.

ISO 200 shots also show excellent detail at 20x30 inches.

ISO 400 shots are slightly soft, but still show good detail at 20x30 inches.

ISO 800 images look great at 13x19, but were a little soft at 20x30 inches.

ISO 1,600 images print well at 13x19, with a little noise appearing in the shadows, but it's not as bad as on the A55.

ISO 3,200 files are a little too soft printed at 13x19 inches, but they look better at 11x14. There is some color fading, but it's not too bad.

ISO 6,400 shots are usable at 8x10, but really look better at 5x7.

ISO 12,800 images are a little grainy at 5x7, but shape right up when printed at 4x6 inches.

Overall, very impressive results from the Sony A33, producing a usable print from every ISO setting.

Testing hundreds of digital cameras, we've found that you can only tell just so much about a camera's image quality by viewing its images on-screen. Ultimately, there's no substitute for printing a lot of images and examining them closely. For this reason, we now routinely print sample images from the cameras we test on our Canon Pro9000 Mark II studio printer, and the Canon Pixma MP610 here in the office. (See the Canon Pixma Pro9000 Mark II review for details on that model.)

Viewfinder

Sony A33 Viewfinder

The Sony A33 features a translucent mirror design that necessitates use of full-time live view, and so adopts an electronic viewfinder, rather than the true optical viewfinder of a traditional SLR. (While it would perhaps have been possible for Sony to adopt a true optical viewfinder using light reflected by the translucent mirror, as was done with certain film SLRs in decades gone by, it would by necessity have been very dim. Hence, the decision to use an EVF is undoubtedly the correct one.)

An important advantage of the Sony A33's electronic viewfinder, as compared to a tradition SLR's optical viewfinder, is that the effect of white balance, exposure settings, and the like can be previewed. This allows the photographer to better understand what to expect from their final image. Also, since an EVF can display essentially anything the main LCD can, it allows you to view the same overlays that you'd see on the LCD, including things like a live histogram that would be simply impossible with an optical viewfinder. (A full list of the possible overlays that can be shown on the electronic viewfinder can be found on the A55's Operation page. The only display mode offered by the A33's LCD that isn't available on the EVF is a full-screen status display that simply wouldn't make sense to use with the viewfinder, since it would prevent any view of the subject itself.) If you're suitably familiar with the A33's external controls, the EVF even allows you to browse menus and quickly change settings without taking the viewfinder away from your eye. Optical viewfinders have advantages of their own, though. They use no battery power, providing a significant advantage over framing images on an LCD display -- and this is particularly significant given that the A33's EVF actually uses more power than the main LCD panel does. (Battery life with flash usage, to CIPA standards, is rated as 340 shots when using the LCD, but falls significantly to 270 shots with the EVF.) There's also something to be said for the image viewed through a really nice optical viewfinder, something even the best electronic finders struggle to match with current technology.

We don't currently have details on the precise viewfinder type employed by the Sony SLT-series cameras, but Sony describes it as a 0.46-inch diagonal (0.43-inch effective) Xtra Fine LCD Tru-Finder. Whatever the type, it clearly employs a time-multiplexed method to display red, green, and blue color information at every pixel location, suggesting that it is likely to be a ferroelectric LCD. These differ from traditional LCD displays, which mostly create color information with a cluster of three adjacent red, green, and blue subpixels (commonly called 'dots'), for each pixel location. When compared to standard LCD electronic viewfinders, ferroelectric types bring both advantages and disadvantages. They've proven somewhat divisive in the past, due to their tendency to demonstrate RGB "rainbow" artifacts when you blink or move your eyes, or with fast-moving subjects. On the positive side, though, since each pixel provides full color, ferroelectric LCDs tend to look much smoother and more detailed than their traditional LCD siblings, with less obvious pixel structure. They also tend to have higher refresh rates, and indeed Sony specs the EVF used in the A55V, A55, and A33 as offering a 60Hz refresh rate. It's perhaps not surprising to see such a display adopted by Sony, since Konica Minolta -- the company Sony absorbed to create its DSLR division -- was a particular proponent of their use.

We're pleased to report that the EVF in the Sony A55V, A55, and A33 provides better dynamic range than most. Resolution is good, with no noticeable gaps between pixels, and the EVF also does a decent job of preserving highlight detail in high-contrast scenes. The slight distraction caused by the "rainbow" effect is relatively easy to ignore in most usage. In spec sheets for the A33, Sony lists its EVF as having 1,440,000 dots, of which 1,152,000 are effective in the viewfinder display. We believe that the company is following precedent here, by simply reporting a dot count as if each pixel constituted three separate color dots, rather than being time-multiplexed. If that's the case, the actual pixel resolution would be 480,000 total pixels, of which 384,000 are effective in the final image.

It's a little unusual to see an effective pixel resolution for an electronic viewfinder, but we believe the reason effective resolution is some 20% lower than the EVF's actual pixel count is that Sony have selected an LCD with approximately a 4:3 aspect ratio, but are only using the central 16:9 aspect ratio swathe of the display. This is likely done both to match the rear-panel LCD display aspect, and also because even with this crop, the EVF already has a generous 1.1x magnification -- much higher than that of most APS-C DSLRs -- and a somewhat tight eyepoint of 19mm from the viewfinder eyepiece (18mm from the eyepiece frame). Were the whole display used, the eyepoint would fall uncomfortably low -- it's already just a little tight for eyeglass wearers. Thankfully, it includes an unusually wide -4 to +4 diopter adjustment range, better mitigating the tight eyepoint for those with eyeglass prescriptions inside this range. The EVF also has a 100% field of view, and provides three step automatic / manual brightness control.

A pair of horizontal infrared sensors, visibly just beneath the viewfinder in the image above, detect your eye as it approaches, and deactivates the tilt / swivel LCD display if you have the Finder / LCD Setting option in the Custom menu set to "Auto". Alternatively, you can disable this function and switch between displays manually, using the Finder / LCD button. This might be advisable if you tend to leave the camera switched on and hanging on its neckstrap, given that it can't differentiate between your eye and chest, and will potentially waste battery life by switching to the more power-hungry EVF panel. You can also set the infrared sensors to initiate autofocus whenever your eye is in range of the eyepiece (Eye-Start AF), which makes the A33's autofocus seem even more responsive.

Viewfinder Test Results

Coverage
Excellent accuracy from the electronic viewfinder and LCD monitor.

The Sony Alpha SLT-A33's electronic viewfinder and LCD monitor showed slightly above 99% coverage with our Sigma 70mm f/2.8 prime lens. This is excellent performance, though not a surprise given the viewfinder is electronic and is deriving its image from the main imaging sensor.

Video

Sony A33 Video Recording

Over the last couple of years, high-definition video capture has become a fairly common feature for interchangeable-lens cameras, available in many single-lens reflex and single-lens direct view cameras at all price points. In all cases, though, focus adjustment during video capture has either been restricted solely to manual focus, or rarely, via contrast detection autofocus based on data streamed from the image sensor. Phase detection AF -- the system used for still image capture in an SLR camera -- simply isn't possible during video recording for a traditional SLR, because once the mirror is raised to expose the image sensor, there's no way to redirect light from the optical path to the dedicated phase detection AF sensor. Pulling focus manually isn't for everyone, though, as it's a notoriously difficult skill to master. Contrast detection AF isn't perfect either, as compared to phase detection AF, it's generally rather slower, and less able to cope with moving subjects. It also requires focus adjustment in repeated small steps, with some hunting around the exact point of focus, and tends to lag briefly behind subjects with unpredictable movement.

The radical design of Sony's Alpha A33 changes all that, allowing phase detection autofocus during video capture for the first time. This is achieved with a pellicle mirror -- or in Sony parlance, a Translucent Mirror -- which reflects around 30% of incoming light to a phase detection autofocus sensor located in the flash / electronic viewfinder housing, and transmits the remaining ~70% of the light to the image sensor. This means that the phase detection sensor receives its share of incoming light at all times, although if autofocus is in use, aperture must be controlled automatically, and is kept at or near its open position. Potential drawbacks of the approach are two-fold. The A33 must increase its gain (and hence, noise levels) to provide the same exposure as a traditional SLR, and since the aperture must remain open when autofocus is available, it must control exposure using shutter speed and ISO sensitivity alone. In bright scenes, the higher framerates used to control exposure can lead to somewhat choppy-looking video.

Video capability. There is no separate video recording mode on the Sony A33: Video can be initiated from any still-capture mode by pressing the video Movie button on the angled rear face of the body.

Of course, since the A33 uses a standard Sony Alpha mount, available lenses will have been designed with still image AF in mind. This means that AF drive noise is more of an issue than would be the case when using lenses designed for video, such as in Sony's NEX-series single-lens direct view cameras. With that said, the phase detection autofocus means less hunting, and --- since phase detection systems can provide immediate information on the size and direction of AF adjustment required -- more direct AF operations, perhaps resulting in less noise than would be the case with a traditional SLR using the same lenses for contrast detection AF. For the amateur videographer desiring autofocus during video capture, the AF noise is likely a relatively small price to pay. It can also be further mitigated thanks to the A33's external, stereo microphone connection, which allows the use of a quality directional mic and some form of isolation mechanism that will also reduce the impact of body handling noise.

Its lack of manual control over video exposure parameters means that the Sony A33 may not be a choice for serious video aficionados, but it does offer a modicum of control over the look of videos, with the ability to adjust exposure compensation and lock exposure during recording, and to select a creative style, white balance mode, metering mode, or AF area before recording. (If the AF area is set to local, it is also possible to change the active AF point during recording.) All things considered, the Sony A33 (like its simultaneously announced siblings, the A33V and A33) offers an interesting first among interchangeable lens cameras, making phase detection video autofocus not only a possibility, but a reasonably useful proposition. Let's look at its video capabilities in a bit more detail:

Sony A33 Basic Video Specs

• 1080i (1,920 x 1,080), 59.94i (interlaced) fields/second, 17 Mbps HD recording (50i in European versions) in AVCHD format
• HDV 1080p (1,440 x 1,080 rectangular pixels), 29.97 fps, 12 Mbps, HD recording (25 fps in European versions) in MPEG-4 format
• VGA (640 x 480), 29.97 fps, 3Mbps standard-definition recording (25 fps in European versions) in MPEG-4 format
• Movies don't use full sensor area, and so increase effective focal length slightly.
• Maximum clip length is 2GB or 29 minutes
• Full-time phase detection autofocus functions during movie recording, with any autofocus-capable Alpha-mount lens
• Automatic exposure with aperture locked at or near wide open position if using autofocus (exposure brightness controlled with shutter speed and gain adjustment)
• Automatic or Aperture-priority exposure if using manual focus
• Exposure compensation and exposure lock are available both before and during movie capture
• SteadyShot image stabilization, white balance, creative style, metering mode, and AF area can be set before movie capture begins
• Maximum clip length is greatly reduced to just 11 minutes, if SteadyShot is enabled
• If AF area is set to local, AF point can be changed during movie capture
• Stereo audio recording via built-in microphones or via a standard 3.5mm external mic jack
• Audio recording can be disabled altogether
  
  

Sony A33 Video: Image Size, Frame Rate, and Encoding

The Sony A33 records at three different video resolutions, and can record high-definition movies in either AVCHD or MPEG-4 formats. Audio is encoded during movie recording in Dolby Digital (AC-3) for AVCHD and AAC-LC for MPEG-4. No spec is provided for the sampling rate of the audio tracks, though video players report 48 kHz at 256 kbps for AVCHD and 48 kHz at 128 kbps for MPEG-4.

The table below shows the specs for various video recording options.

As noted above, the Sony A33 offers two video recording formats, either the HD-only AVCHD format or the less space-efficient but more computer-friendly MPEG-4. The MPEG-4 file format is a bit less efficient in its use of memory card space for a given image quality level, but is more widely supported, and seems to be a bit easier for older computers to read. AVCHD is the best choice if your primary output is going to be directly to a HD television, but MPEG-4 probably a better choice for your computer, particularly if it's more than a year or two old.

In AVCHD mode, the pixel resolution is 1,920 x 1,080, and the data stream on our test sample seemed to be recorded at an average rate of 2.1 MB/second, the maximum rate according to the "Main Profile" spec for AVCHD. No options are offered for lower bit rates, but in our experience, there wouldn't be much point to them: We've generally found lower AVCHD bit rates to result in poor detail and excessive artifacts, especially in higher-resolution and higher frame-rate cameras. At ~17 Mbits/second, file sizes are modest enough that we see little or no benefit in greater compression. (You'll definitely want to buy a really big SD card for use with your A33, though: Even with AVCHD compression, video files take up a lot of card space.)

With a frame rate of 60 fields-per-second (interlaced), the Sony A33 produces smooth motion, though not as smooth as could be possible with a sensor running natively at 60i. The A33's sensor is read at 30 frames-per-second (progressive) and video is interlaced to 60i by extracting alternate field pairs of each 30p frame. (The AVCHD standard does not define 1,920 x 1,080 at 30p, so providing 60i from a 30p sensor makes perfect sense.) While this is not true 60i from the sensor, it does have the advantage of making de-interlacing much easier, though sophisticated de-interlacers can certainly produce more fluid looking motion from true 60i video.

MPEG-4 mode offers a choice of two resolutions both recorded at 30 frames/second (progressive), with data rates and compression ratios as detailed in the table above. The MPEG-4 formats on the Sony A33 actually use slightly less memory card space than does its AVCHD format. This may in part be due to their lower frame rate, but also reflects the reduced resolution and significant compression that the A33 applies to these files.

There's an interesting difference in the high-def video capture functionality between the Sony A33, and its siblings, the A55 and A55V. Where the higher-res cameras use the entire effective area of the image sensor to capture movies, the A33 uses a window that's somewhat smaller than that used for still imaging. The result is a slight increase in the focal length crop when shooting movies, although Sony doesn't provide a precise figure for the increase. The LCD and electronic viewfinder previews match this cropped area, and so users may well not even notice the difference, but it's worth noting in that it will make truly wide-angle high-def video just slightly harder to achieve with the A33, compared to its siblings (and conversely, making it slightly easier to record at longer effective focal lengths). The difference is likely due to a limitation in how the A33 clocks a video stream off its sensor, preventing Sony from using the entire sensor area at the required frame rates. Note that VGA movie recording doesn't suffer this additional focal length crop.

Sony recommends use of a Memory Stick PRO Duo Mark 2, Memory Stick PRO-HG Duo, or SD / SDHC / SDXC Class 4 rated memory cards for movie recording, to ensure that card write speed isn't a limiting factor in clip length. (Slower cards will likely still work to some degree, but with a reduction in clip length, especially in AVCHD mode.)

Here are some examples of video shot with our sample of the Sony A33:

Sony A33 Video Samples
AVCHD 1920 x 1080, 60i (28.0 MB)	MPEG-4 HD quality 1440 x 1080, 30p (15.9 MB)
	MPEG-4 VGA quality 640 x 480, 30p (4.3 MB)
Focus Test Example 1 MPEG-4, HD quality (23.9 MB)	Indoor Lighting Example MPEG-4, HD quality (10.1 MB) [White balance set to Incandescent.]
Focus Test Example 2 MPEG-4, VGA quality (4.9 MB)
Rolling Shutter Artifact Example 1 AVCHD, 1080i (9.7 MB)	Night Video, MPEG-4 MPEG-4 HD quality (21.7 MB)
Rolling Shutter Artifact Example 2 MPEG-4, HD quality (7.2 MB)
Rolling Shutter Artifact Example 3 MPEG-4, VGA quality (2.2 MB)
Note: we hope to add some commentary and analysis when we get the chance, but for now, click on the links to download the videos and see for yourself. Enjoy!

Sony A33 Video-Mode Focusing

Live autofocus during video recording has been one of the main areas in which SLRs and SLDs have lagged dedicated camcorders, ever since video first appeared as a feature on SLR cameras a couple of years ago. It's perhaps not as much of a problem as one might expect, because the lower resolution of video images results in greater effective depth of field than with high-resolution still images, but it's still an issue for many consumers. Arranging camera angles so the subject will stay in the plane of focus for the duration of a clip can help to some extent, as can using smaller apertures to increase the depth of field, but neither works in all situations, and provides an adequate replacement for live autofocus. Of course, you can also learn to "pull focus" while the camera is recording, moving between preset focus points manually, but doing that well requires a surprising level of skill and experience -- and it can be made even trickier with lenses that weren't designed for video use.

Without live AF, consumers for the most part are reduced to only shooting subjects at a constant distance from the camera, or to having to settle for a lot of poorly-focused video -- rather defeating the purpose of recording at high definition resolution in the first place. A lot of video-capable SLRs are being sold to consumers these days, and having some video capability is certainly better than none, but for most consumers to make full use of a video camera, it really needs to be able to focus on the fly. Some single-lens direct view (SLD) cameras, including Sony's own NEX-series, have been able to offer improvements in certain respects, thanks to opportunities arising from their need to create new lens mounts (and compatible lens designs) from the ground up, but they still can't entirely get around the fact that contrast detection autofocus by its very nature requires focus changes to be made gradually in a series of steps, followed by some hunting around the point of focus.

The Translucent Mirror design of the Sony A33 allows it to avoid these issues, by providing full-time phase detection autofocusing during video capture, but the system brings some compromises of its own. Perhaps most significantly, the Sony A33's autofocus functionality during movies relies on the lens aperture being kept at or near the open position, and for this reason, manual aperture control isn't available when autofocusing is enabled during movie recording. Since smaller apertures can't be used to control exposure, this further means that when autofocus is enabled, a combination of adjustments to ISO sensitivity and shutter speed must be used to control exposure in bright lighting. When higher shutter speeds are selected by the Sony A33's autoexposure system, the result can be a noticeable choppiness, because each video frame retains less motion blur on moving subjects. (If you're intending to extract stills from your video, though, the reduced motion blur can potentially be an advantage, with moving subjects more sharply rendered.) This issue can be worked around using neutral density filters to bring the shutter speeds back down, but that of course relies on your having the appropriate selection of filters for your chosen lenses.

The Sony A33's phase detection system functions identically for both still image and movie shooting. There are a total of fifteen AF points, of which three are cross-type points, sensitive to both horizontal and vertical detail. While these points cover a fair portion of the image frame, and it's possible to manually select which point you want to use, they cannot be moved around the frame at will, as you can do with a camera using contrast detection autofocus. (They also don't reach as near to the edges of the frame as is possible when using contrast detection.) Three AF point selection modes are available -- Wide (which automatically selects any of the 15 AF points), Spot (which uses only the central, cross-type point), and Local (which allows direct selection of any individual point). The focusing mode must be selected before movie capture commences, but when set to Local, it's possible to change the active AF point during movie capture -- useful if your subject is moving around the frame, or you want to direct the viewer's attention between multiple subjects in the scene.

Regardless of the autofocus servo mode selected for still image capture, movies always use continuous servo autofocus, so it isn't possible to manually trigger single AF cycles as desired during movie capture. There is a workaround for this, in that you can simply disable and re-enable autofocus during movie recording, using the physical switch on the lens or camera body, as appropriate. Unless the camera's mounted on a tripod, though, this approach is liable to cause camera shake, and of course the sound of the switch being moved will also likely be picked up by the A33's internal microphone. Of course, it's also worth noting that noise from the autofocus drive mechanism is also likely to be picked up on the audio track, unless using an external microphone mounted remotely, or on some form of shock mount.

For more advanced users, manual focus during video recording is certainly an option, just as it is on many video-capable, interchangeable-lens cameras -- and unlike video-capable DSLRs, the A33 allows framing of video not only on its LCD display, but also in its electronic viewfinder (an important advantage when shooting under bright sunlight, when LCD panel glare can make manual focusing even more challenging). The Sony A33's very high resolution LCD display and electronic viewfinder both make this somewhat feasible, but without magnification, even displays this sharp don't quite hold up to 1,920 x 1,080 video resolution. While the A33's LCD and electronic viewfinder are towards the upper end of what's available in terms of resolution, neither provides even half the resolution of a Full HD video frame, and so the AF system could almost always do a noticeably better job of focusing than we could manually. The Sony A33 does offer its users a potential solution for any shortcomings in their manual focusing abilities, thanks to the availability of aperture control when focusing manually. Presuming that there's enough light for an adequate exposure, you can simply stop down the lens further to increase the available depth of field, giving yourself a margin of error around your selected point of focus.

The availability of full-time phase detection autofocusing during movie capture is perhaps one of the most significant benefits of the Sony A33's Translucent Mirror design, and it arguably provides a hugely important benefit for consumers, offering relatively fast autofocusing without the obtrusive hunting that's common in contrast detection AF systems. Since its Alpha-mount lenses weren't designed for video, autofocus drive noise is unfortunately quite obtrusive, but that's an issue that the Sony A33 shares with most video-capable DSLRs. Probably the biggest issue in the design is the requirement that the lens aperture be held open when autofocus is active, which can result in choppy video when shooting in bright conditions. This, coupled with the inability to place a focus point outside the area covered by the phase detection AF points, are probably the most significant drawbacks of the design. Unfortunately, with the availability of full-time phase detection AF in the A33, Sony has chosen not to provide any contrast detection AF capability. Given that both methods have different strengths and weaknesses, we'd have preferred to see Sony offer both systems, allowing the videographer to decide which AF mode was best suited to their subject.

Sony A33 Video Exposure Control

While the Sony A33 lets you record movies directly from any of its still-image exposure modes, including aperture-priority, shutter-priority, and full manual exposure modes, the shutter speed, aperture, and ISO settings for video recording are always automatically controlled whenever autofocus is enabled. Thus, while the camera's menu system might suggest full PASM (programmed, aperture-priority, shutter-priority, and full manual exposure) exposure control for videos, there in fact is no direct control over aperture, shutter speed, or ISO during movie recording.

When focusing manually, however, the Sony A33 offers a choice of either completely automatic exposure, or Aperture-priority exposure. The latter is available only when the Mode dial is in the Aperture priority position, and the camera retains control of both ISO sensitivity and shutter speed, but the ability to stop down the aperture is a particularly useful one when focusing manually, providing a means to increase depth of field (and hence, the chance that your chosen subject is in focus.)

Exposure compensation adjustments made in still-capture modes do carry over into movie recording, provided that there's enough light. (That is, if it's too dark, boosting the EV adjustment won't make your video any brighter.) It's also possible to adjust exposure compensation during movie recording, and to lock the exposure level by holding down the autoexposure lock button. (When released, exposure metering and adjustment will immediately resume.) White balance settings also carry over to video mode, as do the metering modes and creative styles..

Shutter speed is one aspect of video exposure we've recently become more aware of. It turns out that slower shutter speeds tend to produce more natural-looking videos than faster ones: The motion blur associated with a slower shutter speed tends to smooth-out transitions between frames with rapidly-moving subjects: Cameras with 30fps recording, but shutter speeds 1/100 second or higher produce somewhat choppy, artificial-looking movie footage, while cameras with exposure curves biased toward shutter speeds in the 1/30 - 1/60 second range show a lot more motion blur, but the end result looks more natural to the eye. The A33 is more prone to this than traditional SLRs and SLDs, because when autofocus is enabled, the aperture must remain at or near its open position to make phase detection AF possible. This results in the exposure level being controlled with only shutter speed and ISO sensitivity, where other cameras might be able to use a slower shutter speed by stopping down the lens aperture as necessary.

Sony A33 Movie-Mode Image Stabilization

Sony is unique among camera manufacturers, in having both body-based and lens-based image stabilization technology in their product lines. In the case of the A33, image stabilization happens in the body, so its available with all lenses. Sony claims that the SteadyShot INSIDE anti-shake system in the A33 provides a 2.5 to 4-stop reduction in the blurring produced by camera shake. Translating that into real-world shutter speeds, a two-stop improvement means that a shutter speed of 1/30 second would give you the same resistance to blur from camera shake that a speed of 1/120 would without anti-shake. A 4-stop improvement would mean you could shoot as slow as 1/8 second and get the same results (blur-wise) as when shooting at 1/120 second unaided. Even the lower end of the specified range of effectiveness means a pretty significant improvement in one's ability to hand-hold long exposures. Since the A33 uses sensor data to provide a live view feed on either the LCD display or electronic viewfinder, the effect of stabilization is previewed regardless of which display is being used. A SteadyShot scale on the right side of the viewfinder display further indicates the degree of stabilization.

One drawback of the Sony A33's in-body image stabilization is that, when enabled, it greatly reduces maximum clip length. This is likely an indication of heat created by operation of the sensor shift mechanism, leading to the sensor itself heating up more rapidly. When disabled, the Sony A33 can record clips as long as 29 minutes at an ambient temperature of 68F (20C), presuming the file size limit of two gigabytes isn't reached first. With SteadyShot enabled, though, the clip length is slashed by almost two thirds, to just 11 minutes.

Sony A33 Video: Audio recording

External Mic. The Sony A33's optional external stereo mic plugs into a standard 3.5mm jack under a rubber flap on the left side of the camera body.

As with with most video-capable SLR/SLD cameras we've tested, the A33's internal microphones are exquisitely sensitive to noise produced when operating the camera's controls or even moving your hands on the body. Since the A33 accepts standard Alpha-mount lenses which haven't been designed with video recording in mind, autofocus drive noise is also clearly picked up by the camera's internal microphones, although the AF operations are at least brief and direct, perhaps resulting in somewhat less noise than in cameras using contrast detection autofocus.

As with most video-capable interchangeable lens cameras, the Sony A33 doesn't have any provision for manual audio level control, whether working from the internal or optional external mic. Of course, this isn't likely to be an issue for the A33's primary target buyers.

Sony A33 Movie Recording/Playback User Interface

The Sony A33 makes movie recording very easy, as you can initiate it at any time, regardless of the mode-dial setting: Simply press the prominent Movie Record button with the red dot at its center on the camera's top panel, and the camera will start recording video.

Normally, this is where we'd list the Movie-mode menu items, but the A33 has no separate movie menu. In fact, the only menu items exclusively related to video recording are the choice of file format (AVCHD or MPEG-4), the image size (1,920 x 1,080 for AVCHD; 1,440 x 1,080 or 640 x 480 for MPEG), and whether movies should be recorded with or without an audio track.

Playback mode on the Sony A33 is decidedly odd. The odd part is that the A33's playback is an either/or proposition, relative to stills and videos: If you've just shot a video and press the playback button, you'll see only movies that are stored on the card; not the still images. Likewise, if you've just shot a still image, you'll only see other stills when you hit the playback button. To switch between the two modes, you have three options -- either drop into thumbnail view and scroll over to the left, to select the correct tab on that screen, or visit the Playback menu and change the Still / Movie Select option, or simply grab a throwaway exposure of the type you want to view. We actually found it much more convenient to hit the Movie Record button twice (to record a brief video clip) than to navigate through the playback menu to change the playback mode. Sony introduced this playback mode in its NEX-series SLD cameras, where it caused us some consternation until we figured out what was going on. "Where'd all my movies/stills go?" RTM, as they say, but we can only imagine the dismay many users will experience (if only until they read the manual) when they think all their vacation photos disappeared after they'd finally shot a video. Since so few people actually do read manuals, we also suspect this is going to be the source of a lot of service calls to Sony's support centers.

The likely reason for this odd either/or choice for movie/still playback reveals itself when you try to scroll through movies you've recorded, to find a particular one you want to play back: Scrolling through recorded movies is just ineffably slow. Well, perhaps not ineffably; it's a matter of a couple of seconds per movie, but that's slow enough that navigating through more than two or three movies can be seriously painful. Why so slow? The camera is lightning-quick scrolling through still images, and doesn't it save a JPEG thumbnail of each movie, for just this purpose? This is another area in common with the NEX-series cameras that's going to produce a lot of frustration with users.

While it pales beside the slow playback scrolling, we missed one other playback option that's become increasingly common on both digicams and SLDs; namely the "trim" function. Whenever you record a short video clip, it's inevitable that you'll start earlier and keep recording longer than the action you're interested in. (If you don't do this, you're almost certainly going to miss action you're interested in.) While "padding" like this is important and necessary, we like to keep our videos concise by trimming away the extraneous material at the beginning or end of the clip after they're recorded. Many cameras support doing this in-camera these days, but the A33 does not. You could certainly import the video clips to your computer and do the trimming there, but that's awfully cumbersome. Far easier to simply trim and toss away the unwanted footage on the camera. (More grist for the mill for the first firmware update to the A33... ;-)

Rolling Shutter Artifacts

Essentially every video capable digital SLR/SLD currently on the market exhibits some level of motion-related distortion called rolling shutter artifacts. These are caused because the image data is captured and then read off the chip sequentially by rows, rather than each frame's data being captured all at once. In the case of the Sony A33, this means that image data for the last row of a given frame is captured and read out anywhere from 1/25th to 1/60th second after the data for the top row was captured. The effect on moving objects is like that of a focal plane shutter in an SLR, but more pronounced, because the video frame is read out much more slowly than the slit of a focal plane shutter moves across the sensor.

For a camera that scans video frames vertically (as all do that we're aware of), rolling shutter artifacts will be most noticeable for subjects that are moving rapidly side to side, or when the camera itself is being panned horizontally. Verticals in the scene will appear tilted to the right or left, depending on the direction of camera motion. As an example, consider the case of a camera being panned from left to right, with a flagpole or other vertical object in the middle of the scene when recording for a particular frame begins: If the top of the object was centered horizontally when the first line of the video frame is acquired, by the time the last line of the frame has been captured, the bottom of the object will have shifted to somewhere left of center: As a result, the vertical object would appear to be leaning to the right.

Computer Requirements for Viewing HD Video

A typical computer these days has little trouble dealing with still images, but high-definition video can be another matter. Depending on the file format involved, it can take a pretty beefy computer to handle HD-resolution video playback without stuttering or dropping frames. The Sony A33 supports both AVCHD and MPEG-4 recording formats. The AVCHD format is slightly more space-efficient on the memory card relative to its quality level, and displays well on HD television sets, but is less widely supported by computer playback and editing software. If most of your video playback will be on a computer, you may find MPEG-4 to be more to your liking. On the other hand, if your computer supports AVCHD fine, that would be the preferred format, given its space efficiency.

Flash

Sony A33 Flash

The Sony A33 features a built-in, pop-up flash, which operates in either Auto, Fill-Flash, Slow-sync, Rear-sync, Wireless, and Flash-off modes. To release the flash from its compartment, press the button on the left side of the electronic viewfinder / flash housing. Close it again by pushing the flash head back down.

The Flash mode is changed from the Function screen. In Auto flash mode (available only in the camera's Auto or Scene Selection modes), the camera automatically determines when to fire the flash based on the existing lighting, and will pop-up the flash automatically. In Fill-Flash mode, the flash fires with every exposure, regardless of lighting conditions. Slow-sync mode fires the flash for foreground fill exposure, while allowing the background to burn in. The Rear Flash Sync mode fires the flash at the end of the shutter time, rather than the beginning. If you have moving objects in the scene with lights, such as a passing car, this will produce a sharp image of your subject, with a "motion trail" following behind it when shooting at slower shutter speeds. The flash is off when Flash Off mode is selected, or when the flash is down in non Auto exposure mode.

Flash exposure compensation can be set via the Function menu, within a +/- 2-stop range, in 1/3-stop increments. Flash metering options are ADI, which considers focus distance as well as pre-flash light metering, and pre-flash TTL, which considers only exposure metering of the pre-flash. The flash metering mode is selected through screen 2 of the Record menu.

The A33's built-in flash has a Guide Number (GN) of 10 meters or 32.8 feet at ISO 100. That's a bit less than typical consumer SLRs we've tested, which average about 12 meters. Maximum flash sync speed is 1/160 second. High Speed Sync (HSS) shooting with shutter speeds up to 1/4,000s is available with Sony HVL-F58AM and HVL-F42AM external flash units.

A Red-Eye Reduction option is available through screen 1 of the Custom menu. When Red-Eye reduction is enabled, the camera will fire a few low-power flash pulses before it actually snaps the picture, to make the pupils of your subjects' eyes contract.

The A33 also has a top-mounted, proprietary hot shoe for attaching an external flash unit. The shoe design and contact arrangement are set up for Sony's own dedicated flash units.

The Wireless mode lets the Sony A33 work with compatible remote flash units with wireless capability, specifically the Sony HVL-F58AM and HVL-F42AM. Four separate control channels are available for wireless operation, to allow multiple photographers to work wirelessly in the same area without interfering with each other. You're limited to a single external flash unit vs the 3 groups that you can control with Sony's higher-end models, but it still opens a lot of creative possibilities, when the flash doesn't have to be attached to your camera. Operating in Wireless mode with a compatible external flash unit, the Sony A33's flash exposure compensation adjustment can adjust the intensity of the external flash remotely, once the camera and flash unit have been initially synched to each other.

Flash Test Results

Coverage and Range
A somewhat weak flash with uneven coverage at wide-angle. Our standard shot required average exposure compensation.

Coverage. Flash coverage was quite uneven at wide-angle (18mm), leaving very dark corners in our flash coverage test image. Uneven coverage at wide-angle isn't unusual, though. Coverage was much more uniform at telephoto (55mm).

Exposure. The Sony A33 required +0.7 EV flash exposure compensation for our Indoor Portrait test scene, which is average for this shot. The camera's Slow-Sync flash mode produced bright, even results with +0.3 EV compensation, though with a stronger pinkish-orange cast from the room lighting.

Flash Range: Wide Angle
6 ft	7 ft	8 ft	9 ft	10 ft	11 ft
1/60s f3.5 ISO 100	1/60s f3.5 ISO 100	1/60s f3.5 ISO 100	1/60s f3.5 ISO 100	1/60s f3.5 ISO 100	1/60s f3.5 ISO 100
12 ft	13 ft	14 ft	15 ft	16 ft
1/60s f3.5 ISO 100	1/60s f3.5 ISO 100	1/60s f3.5 ISO 100	1/60s f3.5 ISO 100	1/60s f3.5 ISO 100

Flash Range: Telephoto
6 ft	7 ft	8 ft	9 ft	10 ft	11 ft
1/100s f5.6 ISO 100	1/100s f5.6 ISO 100	1/100s f5.6 ISO 100	1/100s f5.6 ISO 100	1/100s f5.6 ISO 100	1/100s f5.6 ISO 100
12 ft	13 ft	14 ft	15 ft	16 ft
1/100s f5.6 ISO 100	1/100s f5.6 ISO 100	1/100s f5.6 ISO 100	1/100s f5.6 ISO 100	1/100s f5.6 ISO 100

ISO 100 Range. With the 18-55mm kit lens, flash exposure started out quite dim at 6 feet at wide-angle but brightened up at 7 feet, and remained bright until 10 or 11 feet where it started to decrease gradually as distance increased. At full telephoto, flash exposure started out bright at 6 feet, but decreased in brightness from then on. Flash exposure was also somewhat inconsistent at full telephoto, with 15 feet being brighter than 14 feet, etc.

Manufacturer-Specified Flash Range
Wide Angle	Telephoto
9.4 feet ISO 100	5.9 feet ISO 100

Manufacturer Specified Flash Test. The Sony SLT-A33's built in flash is rated with a Guide Number of 10m at ISO 100. That works out to about 9.4 feet at f/3.5 and 5.9 feet at f/5.6, the maximum apertures of the kit zoom lens. In the shots above, the Alpha SLT-A33 performs as Sony says it will, producing good exposures at the rated distances with its ISO set to 100 at both wide-angle and telephoto, though results are actually a little too bright (by about 0.25 EV) at full wide-angle. Our standard test method for flash range uses a fixed setting of ISO 100, to provide a fair basis of comparison between cameras. We've now also begun shooting two shots using the manufacturer-specified camera settings, at the range the company claims for the camera, to assess the validity of the specific claims.

High ISO Noise Reduction

Sony SLT-A33 High ISO Noise Reduction

The Sony SLT-A33 offers only two high ISO noise reduction settings: Auto and Weak, with Auto being the default. The A33 user manual does not say at what ISO noise reduction kicks in, so we've included crops starting from the base ISO of 100. We've also included crops from the new Multi-frame Noise Reduction mode, which shoots a burst of six images with a single press of the shutter button and combines them in-camera to average out a lot of noise.

See for yourself how the noise reduction works under daylight-balanced lighting. Click on any of the crops below to see the corresponding full-sized image.

High ISO Noise Reduction Comparison Daylight-balanced illumination
	Weak	Standard	Multi Frame
I S O 1 0 0
	Weak	Standard	Multi Frame
I S O 2 0 0
	Weak	Standard	Multi Frame
I S O 4 0 0
	Weak	Standard	Multi Frame
I S O 8 0 0
	Weak	Standard	Multi Frame
I S O 1 6 0 0
	Weak	Standard	Multi Frame
I S O 3 2 0 0
	Weak	Standard	Multi Frame
I S O 6 4 0 0
	Weak	Standard	Multi Frame
I S O 1 2 8 0 0
	Weak	Standard	Multi Frame
I S O 2 5 6 0 0	N/A	N/A
	N/A	N/A
	N/A	N/A

The above crops show the effects of the Sony A33's two high ISO noise reduction settings, plus Multi-frame Noise Reduction under our studio HMI lighting we use to simulate daylight. As you can see, the "Weak" setting does result in more chroma noise than the Auto, but it also smudges the detail in the red fabric at higher ISOs. (You can really see a difference at ISO 1,600 and above.)  Multi-frame Noise Reduction takes a burst of 6 shots and combines them to average out noise. This new mode is similar to Hand-held Twilight, but gives you control over ISO and exposure mode (PASM). It produces some very clean, detailed images and also extends the available ISO settings to 25,600, but requires the use of a tripod at slower shutter speeds, so similar results can be obtained by simply shooting at a lower ISO with longer exposures if you're already using a tripod.

Let's see how the Sony A33 compares the Canon T1i, Nikon D5000 and Sony A560, which are similarly priced.

High ISO Comparison with Canon T1i, Nikon D5000 and Sony A560 (In-camera JPEGs, all default NR) Daylight-balanced illumination
	Sony A33	Canon T1i	Nikon D5000	Sony A560
I S O 8 0 0
	Sony A33	Canon T1i	Nikon D5000	Sony A560
I S O 1 6 0 0
	Sony A33	Canon T1i	Nikon D5000	Sony A560
I S O 3 2 0 0
	Sony A33	Canon T1i	Nikon D5000	Sony A560
I S O 6 4 0 0
	Sony A33	Canon T1i	Nikon D5000	Sony A560
I S O 1 2 8 0 0			N/A ISO 12,800 not supported
			N/A ISO 12,800 not supported
			N/A ISO 12,800 not supported
	Sony A33	Canon T1i	Nikon D5000	Sony A560
I S O 2 5 6 0 0		N/A ISO 25,600 not supported	N/A ISO 25,600 not supported
		N/A ISO 25,600 not supported	N/A ISO 25,600 not supported
		N/A ISO 25,600 not supported	N/A ISO 25,600 not supported

Here, we can see the Sony A33 is competitive in terms of noise performance in this group, at least in its JPEGs. The 12.3-megapixel Nikon D5000 still has the edge overall, especially when it comes to rendering the red leaf pattern at higher ISOs, though that's no surprise considering its larger photosites. Compared to the Canon T1i, the A33's images exhibit lower luminance and chrominance noise, and the Sony also doesn't smudge the red leaf pattern nearly as much as the Canon at higher ISOs, but the output from the Sonys is a bit softer overall. To our eyes, the A560 does slightly better than the Sony A33 in terms of noise, even though they share the same sensor. This is likely because the translucent mirror in front of the A33's imager is reducing the amount of light striking the sensor (by some 30% or about 1/2 f-stop). The Sony A33's sensor gain has probably been increased to compensate, resulting in slightly higher noise levels under the same conditions. That's just a theory, though. We'll know better once we can examine the A33's RAW files with a raw converter that doesn't apply noise reduction (dcraw).

Note that the last set of crops here were taken with Sony's new Multi-frame Noise Reduction feature, so noise levels are vastly lower than they would be if the cameras supported ISO 25,600 in the standard single-capture mode.

Imatest Results

Sony A33 Imatest Results

We routinely use Norman Koren's excellent "Imatest" analysis program for quantitative, thoroughly objective analysis of digicam test images. I highly recommend it to our technically-oriented readers, as it's far and away the best, most comprehensive analysis program I've found to date.

My comments below are just brief observations of what we see in the Imatest results. A full discussion of all the data Imatest produces is really beyond the scope of this review: Visit the Imatest web site for a full discussion of what the program measures, how it performs its computations, and how to interpret its output.

Here's some of the results produced by Imatest for the Sony A33:

sRGB Accuracy Comparison
Sony A33	Sony A55	Sony NEX-5	Sony A560	Canon T2i	Nikon D90

In typical Sony fashion, the A33 showed generally good color accuracy, with only minor oversaturation of bright reds and deep blues, and to a lesser extent, some oranges, greens, purples and browns. Hue accuracy was also generally good, with the typical (typical meaning significant) cyan shift we see in most cameras we test, and also a little shift in other colors such as aqua, red, orange and yellow. Average saturation for the Sony A33 was 109% (oversaturated by 9%). Average "delta-C" color error was 4.53 after correction for saturation, while not quite as good as the Canon T2i and Nikon D90, still places the A33 in the top tier. (Delta-C is the same as the more commonly referred to delta-E, but delta-C takes into account only color differences, ignoring luminance variation.) All in all, a very good color response for this class of camera. Mouse over the links below the illustration above to compare results with the others in this group.

Adobe RGB Accuracy Comparison
Sony A33	Sony A55	Sony NEX-5	Sony A560	Canon T2i	Nikon D90

Most SLRs/SLDs oversaturate colors when shooting in Adobe RGB mode, and the Sony A33 follows suit. Average saturation was 113.3% which is higher than the sRGB result (though not as high as some of the others in this group), and average saturation-corrected hue error was 4.75 "delta-C" units, just slightly less accurate than sRGB. A typical result. Again, mouse over the links below the illustration above to compare results with the same group.

This image shows how the Sony A33 actually rendered the colors of the MacBeth chart, compared to a numerically ideal treatment. In each color swatch, the outer perimeter shows the color as actually captured by the camera, the inner square shows the numerically correct color after correcting for the luminance of the photographed chart (as determined by a second-order curve fit to the values of the gray swatches), and the small rectangle inside the inner square shows the numerically correct color, without the luminance correction. This image shows the generally very good hue and saturation accuracy. Most colors are rendered reasonably close to the correct brightness, the most obvious exceptions being the red and cyan swatches, which are noticeably brighter than the luminance-corrected versions. Overall, though, the Sony A33's color is quite good.

The bottom row of the chart shows exaggerated white balance errors, revealing that the camera produced a slightly cool color balance when using Custom white balance, with a WhiBal card as the reference.

As always, there's more in this particular graph than we really have room to go into here. (Also note that this set of plots has also changed a few revisions back in Imatest. Some of the plots that were once shown here are now shown in other Imatest output. Since we largely focus on the Noise Spectrum plot, we only show the graphic above, which includes that plot.)

In comparing these graphs with those from competing cameras, we've found that the Noise Spectrum graph at lower right is often the most important. Cameras that manage to shift their noise spectrum to higher frequencies have much finer-grained noise structures, making their noise less visually objectionable. In the graph above, this would show up as a noise spectrum curve that remained higher on the right side, representing higher noise frequencies.

Above, we see the results at ISO 100. The luminance curve is reasonably flat, but the red, blue and green channels exhibit much higher noise values at lower frequencies. The dominance of low frequencies in the color channels points to some low-level blotchiness. Overall noise levels are moderately low, as indicated by the upper right and lower left plots, but slightly higher than the A55. Some chroma noise blotches can be seen in darker midtone and shadows of the Sony A33's ISO 100 images, but only with extreme pixel-peeping.

Above is the same set of noise data at ISO 1,600. Here, the overall Noise Spectrum graph is shifted a fair bit toward the left-hand, lower-frequency side than it was at ISO 100, coarsening the "grain" of the image noise patterns. There's much less difference between the color channels in this plot, with green and blue channels tracking luminance noise very closely, and only the red-channel noise being a bit elevated at the lowest frequencies, no doubt due to noise reduction processing. This translates to ISO 1,600 images with pretty low levels of chroma noise, while luminance noise is competitive to, or slightly higher than other models in its class.

Here's the same set of noise data at ISO 3,200. Here again, the Noise Spectrum graph is shifted even more toward the left-hand side, coarsening the "grain" of the image noise patterns further. Overall noise levels are again slightly higher than its sibling and competitors.

This chart compares the Sony A33's noise performance over a range of ISOs against that of a few other SLR and SLD cameras. While we continue to show noise plots of this sort because readers ask for them, we each time point out that the noise magnitude is only a small part of the story, the grain pattern being much more important, not to mention what the camera does to achieve a given noise level. (Some cameras obliterate subject detail along with noise, so the camera with the lowest noise levels on MacBeth chart swatches may not necessarily produce the most appealing images.)

Here, the Sony A33's luminance noise is slightly higher than most of the cameras in this group across much of the ISO range. Sony's recent advances in noise reduction techniques continue to work well to maintain very good levels of detail in A33 high ISO files while keeping noise in check. However, compared to the NEX-5 and A560, the A33 is at a disadvantage. This is because the sensor's gain has likely been boosted to compensate for the loss of light caused by the translucent mirror. Still, all things considered, the Sony A33's high ISO performance is quite good, though we wish Sony would have provided more flexibility in noise reduction settings (there are only two: "Weak" and "Auto", with the above results taken at the default "Auto" setting).

 

Sony A33 Dynamic Range Analysis

A key parameter in a digital camera is its Dynamic Range, the range of brightness that can be faithfully recorded. At the upper end of the tonal scale, dynamic range is dictated by the point at which the RGB data "saturates" at values of 255, 255, 255. At the lower end of the tonal scale, dynamic range is determined by the point at which there ceases to be any useful difference between adjacent tonal steps. Note the use of the qualifier "useful" in there: While it's tempting to evaluate dynamic range as the maximum number of tonal steps that can be discerned at all, that measure of dynamic range has very little relevance to real-world photography. What we care about as photographers is how much detail we can pull out of the shadows before image noise becomes too objectionable. This, of course, is a very subjective matter, and will vary with the application and even the subject matter in question. (Noise will be much more visible in subjects with large areas of flat tints and subtle shading than it would in subjects with strong, highly contrasting surface texture.)

What makes most sense then, is to specify useful dynamic range in terms of the point at which image noise reaches some agreed-upon threshold. To this end, Imatest computes a number of different dynamic range measurements, based on a variety of image noise thresholds. The noise thresholds are specified in terms of f-stops of equivalent luminance variation in the final image file, and dynamic range is computed for noise thresholds of 1.0 (low image quality), 0.5 (medium image quality), 0.25 (medium-high image quality) and 0.1 (high image quality). For most photographers and most applications, the noise thresholds of 0.5 and 0.25 f-stops are probably the most relevant to the production of acceptable-quality finished images, but many noise-sensitive shooters will insist on the 0.1 f-stop limit for their most critical work.

The image below shows the test results from Imatest for an in-camera JPEG file from the Sony A33 with a nominally-exposed density step target (Stouffer 4110), and its settings such as DRO and HDR turned off.

Here, we can see that the tone curve maintains excellent gradation in the highlights though the shadow end doesn't trail-off quite as nicely.  Still, these results are very much on par with those from the best SLRs with APS-C sensors, with an Imatest score at the highest quality level in the top 10 cameras we have tested.

Processing the Sony A33's RAW (.ARW) files through Adobe Camera Raw (ACR) version 6.2 increased dynamic range by about 1.7 f-stops at the highest quality level (9.37 f-stops), compared to the in-camera JPEG (7.67 f-stops) while total dynamic range reported increased from 10.8 to 11.8 f-stops. These results were obtained by using ACR's automatic settings; slightly better results may be possible by manually tweaking from there, but we weren't able to improve on them. It's worth noting here that ACR's default noise reduction settings reduced overall noise (see the plot in the lower left-hand corner) relative to the levels in the in-camera JPEG, which would tend to boost the dynamic range numbers for the High Quality threshold. Also, the extreme highlight recovery being performed by ACR here would likely produce color errors in strong highlights of natural subjects.

Dynamic Range, the bottom line:

The net result was that the Sony A33 showed excellent dynamic range, performing at least as well as the A55 and NEX-5 (within the margin of error). What's more, it's really in the upper percentile ranking of all the cameras we've tested with APS-C sensors. A very impressive performance.

To get some perspective, here's a summary of the Sony A33's dynamic range performance, and how it compares to other digital SLRs that we also have Imatest dynamic range data for. (Results are arranged in order of decreasing dynamic range at the "High" quality level.):

Note that this test is repeatable to within 1/3 EV according to the Imatest website, so differences of less than 0.33 can be ignored.

Sony A33 Resolution Chart Test Results

The chart above shows consolidated results from spatial frequency response measurements in both the horizontal and vertical axes. The "MTF 50" numbers tend to correlate best with visual perceptions of sharpness, so those are what we focus on here. The uncorrected resolution figures are 2,345 line widths per picture height in the horizontal direction (corresponding to the vertically-oriented edge), and 2,029 lines along the vertical axis (corresponding to the horizontally-oriented edge), for a combined average of 2,187 LW/PH. Correcting to a "standardized" sharpening with a one-pixel radius decreased the horizontal number slightly, resulting in an average of 2,029 LW/PH. The lower standardized versus uncorrected results indicate the default in-camera sharpening is a bit on the aggressive side.

To see what's going on, refer to the plots below, which show the actual edge profiles for both horizontal and vertical edges, in both their original and corrected forms. Here, you can see that the level of in-camera sharpening applied in both the horizontal and vertical directions are slightly higher than ideal. Imatest reports 5.29% of oversharpening in the horizontal direction, and 2.51% oversharpening in the vertical direction. As usual, if you turn the camera's sharpening down a little, you'll get better results when sharpening in-camera JPEGs post-exposure in Adobe Photoshop or other image editing software. (That said, you should be able to extract more fine detail if you begin with a RAW file, rather than a JPEG.)

Note: We don't feature SFR-based LW/PH resolution numbers more prominently in our reviews (eg, outside the Imatest pages) because we've found that they're *very* sensitive to minor differences in in-camera image processing. Relatively small changes in the amount of in-camera sharpening can have a large effect on the resulting resolution numbers. Imatest attempts to compensate for this by adjusting to a "standard" sharpening, but this approach can't completely undo what happens inside the cameras, and so often gives inconsistent results. Sometimes the "standardized" sharpening happens to just match the shape of the edge profile with the in-camera sharpening applied, and you'll get wildly high results. At other times, it will tend to correct in the opposite direction. Unfortunately, ignoring the in-camera sharpening entirely can result in even greater discrepancies, particularly between models from different manufacturers. Turning off sharpening in the camera may or may not fully eliminate the sharpening, so simply turning off sharpening in the camera JPEGs isn't a reliable solution. It also wouldn't be the way most people shoot the cameras. We could process RAW files with no sharpening (as shown below), but then that'd only suit the people working primarily or exclusively from RAW, and would open another can of worms as to what RAW converter was used, etc, etc.

The bottom line is that numbers for resolution only take you so far. Detail handling and edge acuity are very complex issues; ones that don't easily boil down to a single number. The best approach is to simply look look at the broad array of standardized test shots we take with each camera, to the point of downloading and printing them with whatever processing you'd use if you owned the camera and shot with it. See how the differences stack up for you visually, and make your decision on that, rather than on abstract resolution numbers.

RAW Files

Sony SLT-A33 RAW Image Quality

Sorry, but dcraw did not support Sony A33's RAW files at the time this review was posted, so we have no RAW comparison crops for you. You can however download the RAW files yourself and convert them once dcraw or other RAW converters add support. Visit our Sony A33 thumbnails page to download select RAW files.

Menus

Sony Alpha A33 Modes and Menus

When powered on, the Sony A33 is automatically placed into Record mode. The Mode dial on the left side of the A33's top panel lets you select various exposure modes. The Mode dial offers the following selection of shooting modes:

Auto: Proceeding around the Mode Dial in a clockwise direction, the first option on the Sony A33's Mode dial is the Auto mode, which gives the camera control over most exposure variables, including shutter speed, aperture, and ISO sensitivity. The user can still adjust image resolution / compression, aspect ratio, image stabilizer, flash metering, AF illuminator, color space, drive mode, flash m mode (off, auto, or on), face detection, and smile shutter.

Auto+: In Auto+ mode, the Sony A33 still retains control over the same exposure variables as in the standard Auto mode, but also has the ability to recognize specific scene types, and to enable shooting functions not typically available in automatic shooting, such as slow shutter, continuous advance, slow sync / daylight sync flash, and Auto HDR. Scene types that can be recognized in the A33's Auto+ mode include Night View, Hand-held Twilight, Landscape, Backlight Portrait, Portrait, Tripod Night View, Backlight, Macro, and Night Portrait. Recognizing that it might be confusing to less experienced photographers that the A33 can capture multiple image bursts in Auto+ mode, Sony has provided two options in Custom Menu 2 that allow burst shooting in Auto+ mode to be disabled, or to have the camera automatically select only one image from each burst to be saved.

Program AE: In its Program AE mode, the Sony A33 controls both aperture and shutter speed automatically, and you have control over all other exposure variables, including exposure compensation. Unlike many SLRs, the A33 lacks a Program Shift function in its Program mode, however, so without switching to a Priority mode, you're stuck with whichever balance of shutter speed vs. aperture that the camera selected.

Aperture-Priority AE: This mode allows you to manually set the lens aperture (with available apertures depending on the lens in use), while the Sony A33 selects the most appropriate shutter speed. You have control over all other exposure variables, including exposure compensation.

Shutter-Priority AE: The opposite of Aperture-Priority mode, Shutter-Priority AE allows you to set the shutter speed anywhere from 1/4,000 to 30 seconds, while the Sony A33 chooses the best corresponding aperture setting. Again, you have control over all other exposure variables, including exposure compensation. The Bulb setting that's available in Manual Exposure mode isn't available in Shutter-priority AE mode.

Manual Exposure: This mode provides full control of all exposure variables, including independent control of shutter speed, lens aperture, and ISO sensitivity, and hence there is no exposure compensation function. The Control dial adjusts shutter speed by default, and adjusts the aperture when turned while holding down the Exposure Compensation button. The shutter speed range also includes a Bulb setting, allowing long exposures for as long as you hold the Sony A33's Shutter button down. A display in the viewfinder reports whether the Sony A33 thinks your settings will result in under, over, or correctly exposed photos.

Continuous Advance Priority AE: In this mode, the Sony A33 offers its highest shooting rate of seven frames per second, but with some limitations. If Continuous Autofocus is enabled, then the lens aperture is fixed at its fully open position, and ISO sensitivity is controlled automatically. In Single Autofocus mode, aperture and sensitivity can be manually controlled, but shutter speed is controlled manually, and focus is locked from the first frame. Manual focus shooting has the same limitation with regards to shutter speed.

Sweep Panorama: Captures multiple images in a burst for as long as the shutter button is held down, then automatically stitches them into either a 2D panorama, or a 3D panorama that's saved as a multi-picture object file. Focus and exposure are locked from the first frame.

Scene: This mode provides access to the eight preset shooting modes via a Scene Selection menu. Scene modes available are: Portrait, Sports Action, Macro, Landscape, Sunset, Night View, Hand-held Twilight, and Night Portrait.

Flash Off: This mode functions identically to the standard Auto mode, but disables use of flash -- perfect for shooting in situations where flash might prove objectionable, such as in museums.

Playback Mode
The Playback button on the rear panel accesses the A33's Playback mode, which rather unusually allows you to review either captured still images, or movies -- but not both side by side. The left and right arrow keys scroll forward and backward one image or movie at a time, and turning the Control dial has the same effect. The Up arrow key cycles through the various display modes -- image only, image plus basic information, and RGBY histogram with detailed information, of which only the first two modes are available in movie playback. Using the AEL (Enlarge) and Exposure Compensation (Reduce) buttons, you can enlarge captured still images by as much as 11.8x, while the arrow keys pan around the zoomed image. Panoramic images can be automatically scrolled across the screen by pressing the AF (OK) key, and paused with a second press. The same controls are used to play, pause, and cue through movie files. By pressing the Reduce key without playback zoom active, the NEX-5 can also display images or movies in an index format for quick viewing, with either six or twelve thumbnails per page. The index includes tabs on the left hand side with which to switch between still image or movie playback, and this can also be done through a Playback menu option. The A33 also remembers whether you captured a still image or movie most recently, and defaults to entering the Playback type relevant to the last image or movie capture performed.

Sony Alpha A33 Menu Details

Pressing the Menu button provides access to the camera's main menu system, while the Function button calls up the separate Function menu when in Record mode. Below are Sony A33 menu options and their descriptions.

Record Menu 1:

Record Menu 2:

Record Menu 3:

Custom Menu 1:

Custom Menu 2:

Playback Menu 1:

Playback Menu 2:

Storage Menu 1:

Date and Time Menu 1:

Setup Menu 1:

Setup Menu 2:

Function Menu:

Press Release

DSLR Redefined: Sony Introduces New Cameras Powered By World's First Translucent Mirror Technology Enabling Simultaneous Auto Focus And Capture In An Interchangeable Lens Digital Camera

New Models Offer Continuous Phase Detect AF During 10 fps High-Speed Shooting and Full HD Movie Shooting

SAN DIEGO, August 23, 2010 – Sony today introduced two new α cameras (models SLT-A55V and SLT-A33) that adopt Sony’s newly-developed Translucent Mirror Technology™, which achieves the highest-level of auto focus speed for both still image and movie shooting.

Translucent Mirror Technology™ provides performance previously unattainable with traditional DSLR technology. Using the new technology, theα55 andα33 models can continuously and quickly focus (with TTL phase-detection) while shooting stills and recording video—even in full HD, allowing desired moments to be captured in tack sharp focus, high-definition video. They can shoot continuously at up to 10 frames per second on theα55 (and up to seven on theα33), achieving shooting speeds that are the fastest in the industry for an APS-C size sensor-equipped interchangeable lens cameras under $1000.

“This is the most innovative Interchangeable Lens Digital Camera that Sony has ever created,” said Kristen Elder, director of the digital imaging business group. “Our Translucent Mirror Technology is one of the most significant SLR structural changes in more than a decade.”

By displaying the images received by the Exmor™ APS HD CMOS Sensor, picture quality of the camera’s live view image has enhanced drastically. Coupled with the quick and accurate phase detect AF and 100 percent coverage Tru-Finder™ electronic viewfinder, the Quick AF Live View feature has been further advanced.

Translucent Mirror Technology
Both cameras are equipped with a translucent mirror, which enables light passing through the lens to be simultaneously received by the image sensor and the auto focus sensor, allowing continuous shooting and continuous focusing at speeds never before possible. The α55 offers the world's fastest 10 fps high-speed burst shooting with continuous AF (TTL phase-detection) in an interchangeable-lens digital camera with APS-C sensor.

Because of its structure, the Translucent Mirror Technology™ does away with the motion of raising and lowering the mirror. The absence of the moving mirror mechanism contributes to making the whole body size significantly compact compared to traditional DSLR cameras.

By eliminating the need to raise and lower the mirror between shots, the technology makes it possible to achieve focusing while images are captured. Existing systems can only focus in the interval between image capture, limiting the ability to track fast moving subjects. The cameras also have continuous Advance Priority AE Mode and will automatically adjust for the best exposure to help you get the most professional looking results.

High-Speed Capture with Auto Focus
Additionally, a newly developed 15-point AF system assures ultra-fast, high precision focusing. The high-speed shooting with continuous Phase Detect AF tracks rapidly moving subjects accurately. You can capture the decisive moments that you might have otherwise missed.

Creative Video Capture
The continuous phase detect AF also works in movie shooting for the first time in the world. The Translucent Mirror Technology™ also allows the α55 and α33 to be the first cameras to ever maintain continuous phase detection AF while recording Full HD AVCHD video. With fast, precise phase detection AF continually tracking subject movement, even fast action and subjects that move quickly towards or away from the camera are easy to keep in focus.

With a large 16.2 megapixel (for the α55) and 14.2 megapixel (for the α33) Exmor™ APS HD CMOS sensor, background defocusing effects can be easily captured. The APS-C sensor size is nearly 20 times larger than a traditional compact camcorders’ 1/2.88 type image sensor, providing more creative control.

Compatible with all A-mount lenses, video and photography enthusiasts alike can choose from macro to telephoto lenses to achieve their desired artistic effect.

Full-time Live View
Full-time Live View offers unprecedented freestyle shooting versatility with fast, precise AF using either the viewfinder or LCD monitor. The α55 and α33 have a fully articulated 3-inch 921,600 Xtra Fine LCD with TruBlack™ technology with 100 percent coverage.

The Tru-Finder eye-level viewfinder provides an unprecedented combination of 100 percent coverage and 1.1x magnification for easy and natural framing. By combining Translucent Mirror and Tru-Finder technologies, α33 and α55 are the first interchangeable lens digital cameras to offer movie recording with the familiar eye-level shooting style – a significant advantage in fast moving and extreme lighting conditions (bright sunlight and low-light situations).

The variable angle tilt LCD is adjustable to accommodate shooting from low or high angles. The electronic view finder has a high-resolution effective 1.15 million dots conversion Xtra Fine LCD™ display, is bright and easy to see even in low light, has a selectable shooting parameter display and shows the effects of exposure and white balance adjustments.

Advanced Shooting Features
With an Exmor™ APS HD CMOS sensor, BIONZ® high-speed image processing engine and ultra-high ISO sensitivity (ISO 100-12,800), the α55 and α33 cameras offer advanced shooting features. These make it easy to get the best shot, even in difficult lighting conditions.

Auto HDR shoots and combines three frames into a single high dynamic range (HDR) photo with rich shadow and highlight detail. Multi frame NR shoots and combines six frames into a single photo, enabling smooth low-light imaging at half the noise level. Hand-held Twilight shoots and combines six frames into a single photo, suppressing blur to enable clear night-scene imaging without a tripod or flash.

3D Sweep Panorama™ technology creates two images from a single frame, enabling panoramic photos to be viewed in 3D on compatible 3D systems and other devices that support 3D technology. Using the α55 model, built-in GPS capability enables global positioning coordinates to be recorded along with the date and time. HDMI™ connectivity enables stunningly beautiful PhotoTV HD display of images on compatible Sony BRAVIA® TVs.

AUTO+ (Advanced Auto) mode offers the same benefits as Auto mode and more, resulting in cleaner, more dynamic pictures and fewer missed shots. The camera automatically recognizes the correct scene mode, then quickly shoots and combines up to six shots to produce images with greater clarity, optimum dynamic range using Auto HDR technology and lower image noise using 6 shots layering technology.

Accessories
The new cameras accept both Memory Stick PRO Duo™ (including Memory Stick PRO-HG Duo™) and SD (including both SDHC and SDXC formats) media (all sold separately). With a 30MB per second transfer rate, Sony’s Memory Stick PRO-HG Duo HX offers the best performance of all memory cards whether in continuous shooting mode or transferring data to other media.

A new dedicated microphone (models ECM-ALST1 and ECM-CG50) will also be available.

Pricing and Availability
The α55 and α33 cameras will cost about $750 and $650 (respectively) for the body only and about $850 and $750 (respectively) for the body and 18-55mm zoom lens. The α33 camera will be available in September and the α55 model will be available in October at Sony Style® retail stores (www.Sonystyle.com/retail) and at authorized dealers nationwide.

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For information regarding the nearest Sony authorized dealer or service location, call 1-800-222-Sony.