Sony A33 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
Sony A33 ISO Range
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
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
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
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
Sony A33 DRO / HDR
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
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
Sony A33 Sweep Panorama
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 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
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!
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