Sony A850 Review

Overview

Sony A850 Overview

Review by Dave Etchells, Shawn Barnett, and Zig Weidelich
Overview by Mike Tomkins

Full Review Posted: 08/27/09

When it was first announced in September of 2008, the Sony A900 broke new ground in affordability for a full-frame DSLR. Since then, the competition has sharpened, with Canon's EOS-5D Mark II forcing an even lower price point. Now, slightly less than a year after the A900's announcement, the Sony A850 once rewrites the rules again, as the first-ever full-frame digital SLR with a list price of less than $2,000. While it's "only" $700 less than the current price of the A900, this is truly a landmark price point for a full-frame camera, let alone one with 24.6 megapixels of resolution.

Perhaps the most intriguing aspect of the Sony A850 is just how close it is to the A900 (which will remain in the market) in specs and behavior, at a price that's roughly 26% lower. Here's the very short list of differences:

That's it! Sony tells us that the body, sensor, and electronics are identical to those of the A900, and our tests of the Sony A850 bear that out: Image quality is essentially identical to that of the A900, and other performance characteristics apart from the continuous-mode speed and viewfinder coverage appear identical as well. If you've been hungering for an A900 but couldn't quite justify the cost, the Sony A850 is the camera you've been waiting for. And if you've been wanting to get into full-frame digital photography but couldn't previously afford it, this might finally be your opportunity.

Because the body, user interface, sensor, and electronics of the Sony A850 are the same as the A900, the bulk of our verbiage in this review is lifted straight from our review of the A900 last year. We did completely redo our image analysis and performance measurements, though, because we never simply take a company's word for it that a camera or part of a camera is "identical" to another: We always test to verify, and arrive at our own conclusions. In the case of the Sony A850, though, our tests supported the contention that it's the same image-wise as the A900.

So, if you're already well-familiar with our review of the A900, you can save yourself some reading here and make your decision whether or not to buy a Sony A850 based on price and the few differences from the A900's specs described above. On the other hand, if you're new to Sony's flagship DSLR cameras, read on: It's an impressive story.

As with the A900, the Sony Alpha A850 gets a whopping 24.6-megapixel resolution from its full-frame Exmor CMOS image sensor -- the highest sensor resolution of any 35mm digital SLR yet announced. To handle all the data produced by the high-resolution imager, the Sony DSLR-A850 uses dual Bionz image processors, allowing for three frames-per-second shooting for up to 23 JPEG or 16 RAW frames (in our tests).

The sensor is mounted on a moving platter that allows for in-camera image stabilization, branded as SteadyShot Inside. That's another world's first for a full-frame digital SLR, and it's no mean feat when you consider that the sensor shift mechanism has to deal with the extra mass of a full-frame sensor. The various digital SLR cameras seen to date that feature sensor-shift stabilization all have significantly smaller 1.5x crop sensors. Sony rose to the challenge by designing a new more powerful sensor shift mechanism, and rates the Alpha A850 as good for a 2.5 to 4-stop improvement.

Body. The Sony A850's body is magnesium alloy, with large openings for the LCD and lens mount, as well as a cutout for the card door. The battery grip is also magnesium alloy, as shown here. The overall feel is quite solid. The body is sealed against moisture, as are the buttons and dials.

The Sony A850's body is constructed from five main magnesium alloy sections, and includes sealing to reduce ingress of moisture between the body panels, as well as at the various control dials and buttons. The Sony A850 has a Sony Alpha lens mount that also accepts Konica and Konica Minolta glass. A large pentaprism sits above the lens mount, both dictating the camera body's workmanlike visual aesthetic, and providing a very large and bright TTL optical viewfinder with 0.74x magnification. The rear panel features a large 3-inch LCD display with 921,600 dot resolution, equating to VGA (640 x 480) pixel with three R, G, and B dots per pixel. This is used solely for reviewing of images, as well as for menus and status display; the Sony A850 doesn't offer live view capability. There's also a small top-panel status LCD which indicates remaining shots and battery life, as well as the basic exposure variables.

The Sony Alpha A850 offers ISO sensitivity from 200 to 3,200 equivalent, but is expandable to ISO 100 to 6,400 equivalent. Shutter speeds range from 30 to 1/8000 second, plus a bulb setting, and x-sync is 1/250 second (or 1/200 second when SteadyShot is enabled). Metering is achieved by a 40-segment honeycomb sensor, and you can also choose from center-weighted or spot metering modes. Focusing is achieved courtesy of a a nine-point phase detection autofocus system with f/2.8 dual center cross sensor, and there are also ten supplemental AF-assist points arranged adjacent to the main AF points. There's no built-in flash in the Sony A850, with the design instead offering a hot shoe and PC flash sync terminal to allow for external flash strobes and lighting setups.

The Sony A850 has dual flash card slots, and hence can store images on either CompactFlash Type-I or Type-II cards, or on Memory Stick Duo cards. The Sony A850 draws its power from a proprietary NP-FM500H InfoLithium rechargeable battery that's rated for about 880 shots per charge, to CIPA testing standards. Connectivity options include both USB 2.0 High Speed for computer connection, and both standard and high definition video. For standard-def, there's NTSC / PAL switchable composite video output, while high-def is achieved via an HDMI connection.

Sony A850 Pricing and Availability

Pricing for the Sony Alpha A850 is set at US$1,999.95, with availability slated for availability in the US beginning October 8, 2009. The product bundle includes the camera body, battery, and charger, and eyepiece cup. There's also a range of software in the bundle: Image Data Converter SR, Image Data Lightbox SR, Remote Camera Control, and Picture Motion Browser. This last application is Windows-only, while the remainder are included in both Windows and MacOS versions.

Sony A850 User Report

by Shawn Barnett and Dave Etchells

It takes but a glance to see that the Sony Alpha A850 is unique among modern digital SLR cameras. The large, pyramidal shape behind the SONY logo suggests that a very large pentaprism glass element lies underneath. A quick glance through the viewfinder completes the impression: it's like a room in there, into which it seems you might fall if you're not careful. 35mm camera owners from the last century will find the Sony A850's viewfinder comforting, then quickly forget about it and begin composing with an impressive photographic tool.

Like its most advanced sub-frame predecessor the Sony A700, the Sony Alpha A850 is big and boxy, not attempting to appear sleek, it looks more like a big industrial device, as cameras once did. Yet it fits well in the hand: a machine to the eye that is nevertheless well crafted for the human intended to use it.

Its weight is substantial, at 2.07 pounds (939g) without a lens, but with a battery and CF card (that's lighter than the Nikon D700 and just a little heavier than the Canon 5D Mark II); and it measures 6.1 x 4.6 x 3.2 inches (156 x 117 x 82mm). We mentioned the bulk and weight of the excellent Zeiss 24-70 f/2.8 zoom lens in our review of the A900; a natural companion to the A900/850, but one that came at a heavy price, both financially and in terms of weight. Simultaneous with the announcement of the A850, though, Sony also announced a new and very intriguing 28-75mm f/2.8 optic, with is not only substantially lighter (only 20 ounces/565g, vs. 33.3 ounces/955g), but sports a list price that's over a thousand dollars lower than the previous Zeiss optic.

The Sony A850's front panel looks a lot like that of the earlier A700, though the handgrip bulges a bit more into the hand, and the Mode dial is positioned straight and level, while the A700's was mounted at a slant. Missing from the front of the grip is the Grip-sensor that was part of the Eye-start AF system.

Just under the bright orange Alpha logo is the PC flash sync terminal, covered with a rubber flap. Like all other rubber flaps on the Sony A850, this terminal cover swings open and stays open, as it's hinged to the camera, rather than the rubber itself serving as a hinge. That means you don't have to fight with it as you make your connection.

The Sony A850's grip has a comfortable finger groove for the middle finger, in which the infrared Remote Commander sensor is nestled. The inside of the grip is indented for a better finger grip, as is the front of the camera between the grip and lens, which is fairly obvious in the photo above: a very nice touch that those with long fingers will appreciate. Textured rubber surrounds the grip areas both left and right of the lens. The bottom of the body on the left (on the right side in this image) is tapered to allow a more comfortable fit into your palm as you reach your fingers around to the lens barrel.

The rear of the Sony A850 is laid out identically to the Sony A700. Positions are slightly different, with the LCD taking up less of the overall space, mostly because there's more width overall. The left side tapers away just left of the LCD, somewhat minimizing the bulk of the bulge at the left, giving your nose a little break as well, as you move your right eye up to the viewfinder.

Shutter. Just left of the optical viewfinder, you can barely see a latch for the viewfinder shutter. Closing this when shooting on a tripod prevents light entering the eyepiece from affecting the exposure sensor.

The Sony A850's LCD is the same resolution as was on the A700, with 921,600 pixels, and a transflective (both transmissive and reflective) design, meaning that in bright daylight you can still frame images. Checking exposure accurately is a little harder, but that's what histograms are for. Note that though it's a hot feature on many of the latest digital SLRs, the Sony A850 has no live view mode; however, there is a new Intelligent Preview mode that can serve on occasion, and do a few tricks. More on that later.

Note that though there are still infrared sensors beneath the optical viewfinder, these are only for turning off the LCD when you put the camera up to your eye; Eye-start AF is no longer a feature on the Sony A850.

The rear Status display also opens up the option to change many settings right on the screen. Just press the Fn (function) button and use the joystick above it to navigate around the screen. Pressing down on the joystick activates your selection, which you can modify with one or the other control wheel (the rear or front wheel). It'll take a little time to figure out which wheel is necessary for each item, unfortunately. Some use only the front, others use both.

Here's the A900 with the big, beautiful Zeiss 24-70 f/2.8 zoom lens, a fitting if high-dollar mate to the Sony A850. We shot extensively with this lens, and found it to be better than satisfactory, worthy of the A850/900. It also balances out the camera's big body. See our review of this $1,800 lens on SLRgear.com. More intriguing for the A850 might be the new Sony SAM 28-75mm f/2.8 model (shown at right), which is smaller, significantly lighter, and over a thousand dollars less expensive. Watch SLRgear.com, we'll post a review of this new lens there as soon as we can get our hands on a sample!

Now's a good time to point out that there is no pop-up flash on the Sony A850, due partly to the very large pentaprism inside. I think many of the Sony A850's intermediate owners will miss the convenience of a pop-up flash, as an external flash unit significantly raises the weight of an already large and heavy camera.

The Mode dial on the left has only full Auto, Program, Aperture, Shutter, and Manual modes, plus three user-programmable Custom modes; there are no Scene modes. To the right there's a new top status display, one that's very simple compared to most high-end digital SLR cameras. It displays only numbers, usually the shutter speed and aperture values, along with remaining frames available.

Top buttons. Buttons for White balance and ISO are harder to reach with your hand on the grip.

The other four buttons on the top control Exposure Compensation, Drive mode, White balance, and ISO, working in concert with the rear control dial. While the front buttons for Exposure compensation and Drive mode are easy to press, we found the other two a little harder, comfortable with neither the thumb nor forefinger without removing your hand from the grip.

Quality port doors. Ports in clockwise order from the top left: Remote, HDMI, USB/Video out, and DC In.

The Sony A850's rubber doors are the best-behaved doors of this type that we've seen on any camera, swinging open and staying put, rather than flapping shut when you let them go. In clockwise order from the top left, they are Remote, HDMI, USB/Video out, and DC In.

Two card formats. CompactFlash and Memory Stick Duo slots.

Sony A850 owners will have the option of using CompactFlash (including Microdrives) or Sony Memory Stick Duo format. Unfortunately, switching between cards is not automatic when one fills up, as is common on other dual-card digital cameras; still, you can access it on the rear Status display, which turns into an onscreen menu when you press the Fn (Function) button.

SteadyShot INSIDE. Sony says many experts thought adding sensor-shift image stabilization to a full-frame digital SLR would be impossible, but they managed to get it done nevertheless. They're moving a very large sensor at high speeds, so it is quite an achievement. We haven't tested it in the SLRgear.com lab yet, but in casual shooting it seemed to work quite well. Sony states that it offers from 2.5 to 4 stops of exposure latitude.

Though all of us like seeing the stabilizing effects of Canon and Nikon's optical image stabilization through the viewfinder, we also like (very much) the five-bar meter that appears in the optical viewfinder to tell you just how much the SteadyShot system has to work. This lets you pick a moment to trip the shutter when the camera is the most stable, increasing your chances of getting a sharp shot.

The same mechanism activates at startup and shutdown to shake dust from the sensor, and a new anti-static coating has been applied to the outermost glass to reduce the amount of dust that can stick to the sensor. (Note that we've found most anti-dust systems to be only somewhat effective, and the lower shaking frequencies of IS actuator-based systems make them that much less effective than those using a piezo element to produce the vibration.)

Improved EV bracketing. Recent Sony digital SLR cameras were limited to only two automatic bracketing settings: +/- 0.3 EV or +/- 0.7 EV. The Sony A850 allows a full spread of EV options, up to +/- 2.0 EV, a more useful spread.

Interchangeable screens. The Sony A850 comes with a Type G focusing screen, but two additional screens are available: Type M and Type L. Type M, called Super Spherical Acute Matte is superior for discriminating between in-focus and out-of-focus objects, but unfortunately it dims the view somewhat, enough that it's only usable with lenses with maximum apertures of f/2.8 or more. Type L is the same as the very bright Type G, but with a grid for alignment or applying the rule of thirds. As with other digital SLRs that have interchangeable screens, the user has to set the type of screen in Settings menu 3.

Sensor. Sony's Exmor CMOS sensor is what gives the Sony A850 its magic. Above you can see how the A850's size compares to the Sony APS-C-sized sensor. Its pixels are actually larger than those in the Sony A700's 10-megapixel sensor, making for greater ISO sensitivity. The 24.6-megapixel sensor is more than just a sensor, however, as it includes the analog to digital (A/D) conversion circuitry right on board the chip. Over 6,000 A/D converters work in parallel to convert the image data before electronic noise can creep into the signal-processing chain. That makes for fast data acquisition too.

Processors. From there, the dual Bionz processors take the large files and crank them through fast enough to allow up to five frames per second capture, even in RAW + JPEG capture.

Power like that also allows for sophisticated functions like Peripheral Illumination correction, which fixes vignetting problems in many situations.

AF Sensor array. Blue points are the main AF points, oriented in the direction shown. The green blocks are the supplemental AF points.

AF system. The Sony A850 has the same new autofocus system that was introduced with the A900, with nine primary autofocus points and ten supplemental AF points. The user can select the nine AF points, but the ten additional points are used by the system to enhance the performance of the others when the Sony A850 is set to wide-area AF mode. A larger sensor in the center of the frame switches on when lenses of f/2.8 or larger are attached, allowing the system to take advantage of the larger aperture.

If you choose to use the Local AF mode, you can select from the nine AF points in the viewfinder with the joystick on the rear panel. Choose Wide, and the Sony A850 will choose for you. Choose Spot and the Sony A850 uses the more accurate center AF point. See the Optics section for a more detailed discussion of the Sony A850's AF system.

Lens compatibility. While the Sony A850 is compatible with the company's DT-series lenses, many of them, if not most, will vignette significantly with the full frame camera, since they were designed to deliver a smaller image circle to the company's APS-C format cameras. When a DT lens is mounted, the camera automatically captures an APS-C sized frame. Only four thin brackets inside the viewfinder indicate where the cropping will occur; it does not gray-out as seen on the Nikon D3. Incidentally, you can choose to shoot an APS-C sized image when a full-frame lens is mounted via an option on Settings menu 4. The image captured is 11 megapixels maximum in that mode. (Pretty amazing that you can crop the sensor that much and still have 11 megapixels to work with!)

Storage and battery. The Sony A850 uses CompactFlash (Type I and II as well as Microdrives) and MemoryStick Duo cards. The battery pack is the now-standard InfoLITHIUM NP-FM500H, a 7.2V 11.8Wh lithium-ion design, rated for 880 shots (same as the A900).

An optional battery grip is available for the Sony A850, the Sony VG-C90AM, which is light in weight, but increases the height of the overall camera to exceed the height of the Canon 1D-series and Nikon D3.

Still, the battery grip has a few interesting features, including the full array of buttons on the rear that duplicate the controls accessible by the right hand on the camera itself. The Sony Alpha system also uniquely has the unusual second shutter release location that is positioned slightly down from the right corner of the grip, which changes the balance dynamic of the camera. It puts the lens in the same plane with the shutter whether you shoot vertically or horizontally, and does distribute the weight more evenly in both hands if you keep the camera upright and use a lighter lens. The downside is that with a heavy lens, like the Sony 24-70mm f/2.8, most of that weight rests in your left hand.

Physical Comparisons

Sony A850/900 vs Canon EOS 1Ds Mark III

Pro configuration: If you're going to be shooting for long periods, a battery grip is a good idea, but it makes the A850/900 bigger than the comparable EOS 1Ds Mark III. Naturally, you don't have to use the battery grip to enjoy all the quality that the A850 offers.

Sony A850/900 vs Canon EOS 5D Mark II

Smaller full-frame: The Sony A850/900 is just slightly bigger and slightly heavier than the Canon EOS 5D Mark II. The Sony A900 beat the original Canon 5D handily in terms of resolution, but the competition is now close with the 5D Mark II. The 5D Mark II has the advantage of also recording HD video, albeit at a higher price, and minus the rugged injection-molded alloy frame and environmental sealing of the Sony A850/900.

Sony A850 vs Nikon D3x

David vs Goliath?: Here's the Sony A850 next to the Nikon D3x, this time without the optional battery grip that we showed on the A900 in the first comparison above. People have been waiting for/expecting a "D700x" from Nikon for a while now, packing the sensor from the D3x into a compact body, as was done with the the sensor from the original D3 and the subsequent D700. That hasn't happened as of this writing yet, so for now this is as close as you'll find to comparable resolution in the Nikon line.

Using the Sony A850/900

Note: In this section, Shawn writes of his experience with the original Sony A900. Given that the two cameras are the same size and weight and have the same user interface, we've simply copied Shawn's words about the A900 here to the Sony A850 review. Update notes about viewfinder accuracy and frame rate have been added as appropriate, though, calling attention to those two areas of difference vs the A900.

Though the Sony A900 is large and heavy with the Carl Zeiss 24-70mm f/2.8 mounted, I quickly came to accept that burden and just enjoyed shooting with the camera. It's a little like moving from driving a nice car to driving a big truck. Handling is different, somewhat unfamiliar at first, even a little ungainly, but soon you're tooling along like you've been driving a big truck for years.

The big Carl Zeiss optic is beautiful, and both looks and feels terribly precise. Focus and zoom rings are tight and smooth. Even the metal and plastic lens shade is perfection. It mounts to the machined bayonet slot tighter than a piston ring and snaps briskly into place.

Its bulkiness almost makes the Sony A900 look a little more primitive, like some kind of early digital SLR design, or else a film camera from an earlier era. It certainly looks different from other cameras on the market, to be sure.

That big optical viewfinder is wonderful, and it does indeed seem to show 100 percent of the frame, to my surprise. Sometimes it was an unwelcome surprise, because I'm used to framing with tighter, less accurate viewfinders. Often when I thought I'd get away without stepping back to include just a little more of the subject's boundaries in a tight shot, I found that the Sony A900 was instead quite faithful to what I saw in the viewfinder. Gone was the slop I had come to count on from other digital SLRs, whose viewfinders seldom show more than 95 percent of the frame.

A850 note:
This is one key area of difference between the A850 and A900. The view through the eyepiece is still huge compared to sub-frame SLRs; the jokes about being careful not to fall into the viewfinder still apply. The reduction in accuracy might be an issue for some pro users, but the 98% coverage of the A850's viewfinder is still quite noticeably more accurate than the 95% found in most prosumer-grade SLRs. We measured the VF accuracy on our A850 test sample at just a shade under 98% (well within the tolerance of our measurement vs the claimed 98%), and the image was centered to within 0.15 - 0.33% of the frame's height and width, respectively.

Controls. Most controls are well-placed, and the dials and wheels have the appropriate resistance. They're not too firm and not too light, and they don't feel cheap. The mode dial is also quite firm, locking into position well. Though I seldom expect much from joystick controls, the Sony A900's joystick is just right. You can toggle in four directions, and press down to activate many controls. It's especially useful for moving the focus point around in a hurry, as well as for navigating the Function menu.

Two controls are not perfectly placed, though. One is the Function button itself. It's a long reach from the joystick to the button, making the onscreen menu more difficult to use than it should be. Also vexing is how after making a change to a menu item, you're not returned to the Function menu display to make another selection; instead you're dropped back into the Status display. If you want to change more than one item, you'll have to make that reach to the Fn button again.

The other occasional problem control is the Depth-of-field preview button, which I have set to serve as the Intelligent Preview button. I too frequently press this button when shifting the heavy A900 from hand to hand, or while turning it to shoot in vertical format. Intelligent preview exposures take a few seconds to expose and appear, meaning that the camera is occupied for those seconds; more dangerous is that the camera will continue to display the image for some time, waiting for input, thus draining the battery without my knowledge.

Intelligent preview. Sony's innovative use of a limited RAW file to create the A900's Intelligent preview is useful in a number of ways. Though it's meant to be used to subtly tweak a sample image before making the real exposure, I found myself using it more often as a substitute for Live View mode when I couldn't get my eye to the viewfinder. I just pressed the Depth-of-field button to make sample exposure after sample exposure until it was framed just right, then pressed the shutter release. Intelligent preview is really better used for tripod work, where your framing is already set. It's designed to let you pick just the right white balance, exposure compensation, or DRO mode. If you're in Aperture priority mode, you can also adjust your aperture -- though you won't see a depth-of-field change; it's not that good. Similarly, you can adjust Shutter speed if in Shutter priority mode. Of course in Manual mode, you can adjust everything. Intelligent preview is pretty useful.

Many Sony A900 users will wonder why they can't just save the image they've tweaked, rather than take another exposure. The simple answer is that the A900 only captures a very limited-resolution RAW file to make quick, on-camera processing easier, thus delivering an adjusted image to the LCD as fast as you need it. If you accidentally captured that perfect smile when you pressed the Intelligent preview button, though, you'll just have to say goodbye to perfection and try again.

Small AF area.

Shooting. Despite its size, the Sony A900 is really fun to shoot. The big viewfinder makes looking around in your potential image more like detail work than a rough framing job, as it is with most digital SLRs. You can carefully consider what's in focus, and select another focus point by moving the joystick (provided you've chosen to use Local AF area mode) to another position. As with other full-frame SLRs, the diamond-shaped AF array is small relative to the overall viewfinder area, which isn't as good for portrait compositions as you'll find in the A700 or Canon 40D, for example, as it's harder to get an AF point close to one of the subject's eyes in a head-and-shoulders shot.

The shutter sound tells of a very large mirror, one moving as fast as its large size will allow. We're told that the mirror is extra large not just for the full frame, but also to deliver that 100% viewfinder area. (A850 note: We don't know if the A850's mirror is the same size as that of the A900, or slightly smaller. Our contacts at Sony said it's the same mechanism, but tweaks in some unspecified aspects of the mirror/shutter cocking mechanism allowed the trade-off of slower continuous shooting speed to achieve lower production costs and therefore lower selling price.)

The mirror lifts, rather than flips up. It's a pretty cool compromise, necessary to accommodate the large SteadyShot engine, we're told, while still allowing that large mirror. The sound is just a simple click-click, with no winding sound, so it feels nostalgic and does the job without a lot of fanfare. Viewfinder blackout time is supposed to be improved, but it's still a little slower than I like. Again, it's a big mirror.

The Sony A900 is also able to shoot up to five frames per second, quite a feat for a 24.6-megapixel camera with a full-frame sensor. Its 1/8,000 second shutter speed makes it an impressive action camera, rivaling its more expensive high-res competition, the Canon EOS 1Ds Mark III, which also captures five frames per second. The shutter mechanism is rated for 100,000 cycles.

A850 note: This is the other key area of difference in the A850 vs the A900: The A850 only gets to 3 frames/second. Still impressive for such a large mirror and huge amount of sensor data generated by each shot, but a step behind the A900 and most other full-frame DSLRs currently on the market.

Checking. Seeing whether you got the shot after capture is key, and of course the Sony A900's high-res 3-inch LCD really helps on that score. You always have to be careful with transflective displays, however, especially in sunlight. This can be complicated by using DRO modes, which, combined with the transflective display's metallic look, can make you think a shot is washed out more than it is. You can get used to this, and adjust accordingly, as I have, but checking the histogram is also a good habit, as is taking a few extra shots or shooting RAW when the work is critical.

Touching the Custom button (marked with a C) toggles on the Histogram screen, along with most of the exposure data. You get not just a luminance histogram, but red, green, and blue as well to help you gauge color casts.

You can zoom in by pressing the AF/MF button and turning the rear command dial. Zoom level starts at 1.2x and goes to 19x.

One disadvantage to the Playback system on a 24.6-megapixel camera is that it's very slow to bring an image up, especially if it's still writing to the card. I've pressed the Playback button a second time, and then a third, only to have the image finally flash to the screen after three seconds, then disappear for another two seconds, then reappear. Sometimes it gets even worse before I remember to just wait five or six seconds to see where the camera is in the cycle.

Once images are saved to the card, flipping between them is easy, and very fast. Just don't get stuck in Index mode, activated with the Display button. It takes some time to bring up those five thumbnails across the top. It's convenient if you have time, but not if you don't.

Tricked out. Thought I'd include a little eye candy, with the Sony A900 outfitted with a Sony 70-200mm f/2.8 G, the Sony HVL-F58AM flash, and the VG-C90AM battery grip. With two batteries in the grip, the combination weighs 7.63 pounds (3,464g). (The same grip fits the A850 as well.)

The function of the front and rear control dials varies from menu to menu, which can often leave you spinning the dial in vain waiting for something to happen. Sometimes it's one dial, sometimes it's the other, and sometimes it's both. In cases where only one dial controls a given function, it would make more sense for Sony to allow both dials to control the function.

Size has a price. There are those who go for the biggest and the best, and they're likely to slap down their largest credit card on the Sony A900 for 24.6 million little reasons. But while they're at it, I suggest they check their computer hardware and either upgrade or at least invest in redundant, multi-terabyte disks, because the Sony A900's files are huge. A typical outing for me with the Sony A900 is filling a 4GB card in a hot hurry. Some of that's shooting RAW, some of it is just the JPEGs I shoot, which average from 7 to 18MB each. Yes, I said 18MB for a JPEG.

Thankfully, Sony at least planned for the larger files and created a USB download pathway that is among the fastest we've ever tested, moving 12,568 KBytes per second. Still, when you take as many test shots as we do, it's an ordeal to move all these images around. The sample photos we've posted total almost 4GB of data.

Sony A850 Image Quality

Back when we reviewed the original A900, the only other camera with roughly comparable resolution was the $8,000 Canon 1Ds Mark III. Fast-forward just a year, though, and we find the Canon EOS 5D Mark II competing at close to the same resolution level and a price point of about $2,700, as well as the Nikon D3x, albeit at the same lofty $8,000 price as the 1Ds Mark III.

Before I continue my simple analysis, which is bolstered by the other, more in-depth tabs to this review, remember that the Sony A850 is a $2,000 digital SLR intended for both pros and enthusiasts, while the Canon 1Ds Mark III and Nikon D3x models are $8,000 cameras really only meant for pros. (The 5D Mark II is arguably within reach of the well-heeled amateur, but the $700 price premium isn't to be sneezed at.)

First, the Sony A850's image quality is truly awe-inspiring. Opening a file in Photoshop and hitting Command + to get to 100% reminds me of that scene in Blade Runner when Deckard uses the Esper photoanalysis machine. If you know the film, you'll remember that he finds tremendous detail in the print photograph from the year 2019: "Enhance 57 to 19. Track 45 left. Stop. Enhance 15 to 23. Give me a hard copy right there." In the end, he's found a reflection in the mirror that gives him an important clue.

While I'm not doing my searching via voice command (that now-old technology that didn't take hold for most), it takes six enlargement steps in Photoshop to make it from 12.5 percent in portrait orientation to the 100 percent I need to check focus. The image is 4,032 x 6,048, for goodness sake.

Wide detail.

Most astonishing was to take a 24mm wide-angle photo of the World of Coke in Atlanta from across a large field and be able to almost recognize faces standing near the building. (Shot at right, captured with the A900.) You'd actually be able to recognize them, I'm convinced, had I not focused on the buildings in the background. And look at the detail in those buildings! Take anything to 100 percent, and it doesn't seem like a big deal, of course, but start dragging around in the frame once you're there, and you start to appreciate just how much the Sony A850 has captured.

Now let's compare the Sony A850 to some of its near-competitors, resolution-wise. These are crops shot in our lab using a Sigma 70mm f/2.8, the very sharp lenses we use for our lab testing to get more comparable results.

In terms of JPEG shots, the Sony produces larger images that are sharper, especially with the defaults from both cameras, but if you bring both to 100 percent and move around in the images, you'll find they're nearly the same. After all, it's only 3.5 million pixels between the two, and when you get out to 21 megapixels, adding a few more doesn't have that large of an effect. Detail is detail, though, and the Sony does appear to give you more at low ISOs. Some of the difference in the images below is in the sharpness, heavily dependent on the default sharpening, and the presence of luminance and red channel noise from the Sony A850, where the Canon 1Ds Mark III does a little better with those artifacts.

Here are a few samples to get you started, but be sure to explore the full test results on the other tabs of this review, where we go into much greater depth.

Sony A850 Detail vs Competition

Sony A850 vs the Competition: Subtle Detail
Sony A850	Sony A900
Canon 5D Mark II	Nikon D3x
All the images above were shot with the Sigma 70mm f/2.8 macro lens, stopped down to f/8, as the best trade-off between ultimate sharpness and sufficient depth of field to accommodate the 3D objects in the test scene. All shots are at base ISO, ISO 200 for the two Sonys, ISO 100 for the two others. Squinting closely at the results, the image from the Sony A850 appears just microscopically softer than that from the A900. We don't think this is a focus accuracy issue, as elements in the scene closest to and farthest away from the camera seem to be about the same amount softer than the corresponding elements in the shot from the A900. The difference is truly microscopic, though, particularly at the overall resolution level we're talking about here. The smaller size of the image from the 5D Mark II is because of that cameras slightly lower resolution, 21.1 vs 24.5 megapixels. Despite its slightly lower resolution, the 5D Mark II shows slightly more subtle detail, noticeable in the tan frame around the figure and in the khaki-colored background on the label. The D3x's image leaps out at you as being sharper, but a good part of that is the higher default sharpening that the D3x applies to its images. Even allowing for the increased sharpening, the D3x does seem to capture slightly finer detail, but again, doesn't do quite as well as the 5D Mark II in the tan and khaki-colored areas. All four cameras are certainly very, very close, though, particularly when you consider the degree of pixel-peeping we're indulging in here!

Sony A850 vs the Competition: Tone-on-Tone Color
Sony A850	Sony A900
Canon 5D Mark II	Nikon D3x
This shot is a giveaway for the impact of noise suppression in most cameras, particularly in the red fabric swatch. For ultra-high resolution cameras, it's also a tough test of detail, in the thread patterns of the fabrics. Here again, we see some (very) slight differences between the Sony A850 and A900. The thread pattern is a bit more evident in parts of the bright pink fabric swatch, but details in the red fabric look a little softer. There does seem to be some slight difference in the imaging between the two cameras, perhaps in the noise reduction processing. While the 5D Mark II beat the others in its rendering of subtle detail in the previous crops, here it lags behind somewhat, with less definition in the bright pink fabric, and much softer rendering of details in the red swatch. (But it's sharper-looking in the lighter pink patterns in the background. It's interesting how differently each camera's NR processing handles different shades and hues.) The crop from the Nikon D3x again looks sharper, but this time not just due to its cranked up in-camera sharpening, but also because it seems to be going a bit lighter on the noise reduction processing, particularly in the red swatch.

Sony A850 vs the Competition: Sharpening and Fine Detail
Sony A850	Sony A900
Canon 5D Mark II	Nikon D3x
This set of crops probably give the best look yet at the impact of in-camera sharpening. The Sony A850 seems to be applying just a bit less sharpening by default than does the A900 here. In this particular crop, the Canon 5D Mark II seems to have the strongest sharpening of any, but you'll notice elsewhere in the full-size image that the Nikon D3x seems to apply a stronger sharpening effect around the edges of large blocks of dark tone than it does in smaller areas such as the type above. Once again, while you can see differences between the cameras, doing so involves some fairly fine hair-splitting relative to the size of the overall image.

Sony A850 vs the Competition: High-Contrast Fine Detail
Sony A850	Sony A900
Canon 5D Mark II	Nikon D3x
In this final set of crops the raw resolution of the sensors is more evident. Here, the 5D Mark II's 21 megapixel chip shows aliasing in the finest lines, from about 43 on the scale onward. The Sony A850 edges it out in this shot, but is itself slightly eclipsed by the performance of the A900 and D3x. Whether the result of slight differences in the anti-alias filter or in-camera processing, we do see very slight differences in ultimate resolution between the A850 and A900. As we've been pointing out, though, these differences are so microscopic as to be entirely ignored in any practical photographic application.

Sony A850 ISO series vs Canon 5D Mark II

ISO 200	ISO 400	ISO 800
The Sony A850 holds its own very nicely against the Canon EOS 5D Mark II at its base ISO of 200, but the 5D Mark II is the clear winner at high ISO settings. Here is a series from ISO 200 to 800 from both cameras, with images from the Sony on top. You can see that the Sony loses somewhat more detail as it moves up to ISO 800 than does the Canon. And remember, the Canon's lowest "approved" ISO setting is ISO 100. Considering the resolution, we're really pixel-peeping here, but that's the only way to compare two very high quality cameras like these.

Analysis. As with the A900 before it, the Sony A850 presents a bit of a trade-off between detail and image noise. It's a camera with enormously high resolution, but also somewhat higher noise levels at high ISO settings than some of its competition. (Admittedly with some competing models selling for dramatically higher prices.) As with the A900, though, you can also achieve significantly better detail by turning its in-camera sharpening to its lowest setting and sharpening after the fact in Photoshop. And as usual, working from RAW files brings significant benefits.

What's sure is that the Sony A850 plays well against the field, holding its own even against cameras costing up to four times its breakthrough $1999.95 list price. I really enjoyed shooting with the original A900, and had almost as fun looking at the images afterward. The new A850 does indeed appear to offer very similar (if not quite identical) image quality as the original A900 and a virtually identical user experience, save only the slightly cropped viewfinder and somewhat slower continuous shooting speed. That it manages to do so at a list price that's $700 less is pretty remarkable. While the announcement of the Nikon D3x a little while back means that the Sony A850/900 no longer hold the uncontested DSLR resolution crown, the Sony A850 still offers truly amazing resolution for the price. It's not all about resolution, of course: As the last set of pictures above shows, high ISO performance is a very important factor as well, and more expensive models from the competition do still hold an edge in that area.

The most interesting aspect of the Sony A850 is the extent to which it brings full frame photography within the reach of everyman (and woman). Without a doubt, $2,000 is still a lot of money for a camera, so owning a Sony A850 does involve a fairly serious financial commitment. Nonetheless, it represents an important step in bringing full frame photography down to a cost level that non-professionals can afford.

As I've said of other Sony digital SLRs, what's nice about them is that they're relatively easy to use, and simple to learn as well. A well designed menu system, along with the Quick Navi screen make tweaking settings fast and clear, and now the new Intelligent Preview mode makes short work of complicated shots, making it a little easier to pay attention to the small details as you set up a shot.

Shooting with the Sony Alpha A850 can be summed up in one word: Satisfying.

Sony A850 Conclusion

Sony rocked the full-frame DSLR world when they first announced the A900, bringing unprecedented resolution at a price point under $3,000. In the intervening time, Canon announced a camera with slightly lower resolution and a price point below the original A900 (the 5D Mark II), and Nikon announced a camera with similar resolution but at a much higher price point (the D3x). Now, the Sony A850 decreases a couple of specs (viewfinder coverage and continuous frame rate), but brings the cost down to under $2,000. Isn't competition great?

The Sony A850 is a formidable camera. It's big, which won't work for everyone, but I found it more than bearable with my medium-sized hands, and even my daughter had no trouble hefting the A850 with the (very beefy) 24-70mm f/2.8 attached and firing off a few frames. If the image quality is as good as we're hoping for, the new 28-75mm f/2.8 will reduce both the overall price and bulk of a full-frame body/lens kit significantly.

If you want the most pixels in a small package at the best price on the market, the Sony A850 is where you'll find it. Canon's EOS 5D Mark II beats the Sony A850 in high-ISO capability and (slightly) in size and weight, and offers HD video recording as well, but at a price point that's $700 higher. Nikon's D3x offers the same resolution, but at a cost literally 4x that of the A850. If you're into landscapes or architecture, or need a studio camera with enormous resolution at a relatively budget price, the Sony A850 would make a great choice. It truly ushers in a new era of affordability for full-frame DSLR cameras.

Making full-frame digital photography more affordable than ever before, and at a level of 24.6 megapixels to boot, the Sony A850 is one impressive image maker, and a clear Dave's Pick.

Design

Sony Alpha A850 Design

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Sony A850 Front View
Apart from the model number, the A850's front looks identical to the A900.

Sony A850 Left Side
The left side looks nearly identical to the Sony A900, with only a slightly smaller pentaprism housing...

Sony A850 Right Side
...as does the right side.

Sony A850 Top View
Again, the layout and control placement of the top remains the same. The A900's Continuous Hi/Lo drive mode has changed to just Continuous mode for the A850.

Sony A850 Back View
The SonyA850 retains the same layout and control placement as the A900 on the back as well. Viewfinder coverage has dropped from about 100% on the A900 to 98% on the A850. Magnification remains the same, at 0.74x.

Sony A850 Bottom View
Nothing new here, except of course the model number. Even the battery rating (880 shots) is the same as the A900's.

Operation

Sony A850 Operation

This page will seem very familiar if you've read our Sony A900 review, as the Sony A850 is identical to the A900 in operation.

Sony A850 Top Panel Status LCD

The Alpha A850 is the first Sony SLR with a top panel status LCD. This rather small, monochrome LCD displays basic status information such as the current Shutter Speed, Aperture, Exposure Compensation, Battery Status, etc. We like these displays as they give a quick overview of the camera's settings without having to refer to the larger, more power-hungry main LCD when trying to conserve battery life. They also come in handy while adjusting settings when the camera is below eye-level, such as on a tripod. See the illustration below for details on the information displayed.

Sony A850 Top Panel LCD Display Info
Shutter Speed Aperture Exposure Compensation White Balance ISO (Sensitivity) Drive Mode	Battery Remaining Remaining Number of Recordable Images

Sony A850 Record Mode Displays

The Sony A850's rear-panel, 3.0-inch, 921,600 pixel TFT color LCD monitor is for image review, status display, and menu display. Unlike the A300, A330, A350 and A380, the Alpha A850 doesn't offer any form of live view mode, so the LCD can't be used to frame shots. We do really like the wealth of camera information that the A850 makes available on its rear screen, especially since the top panel status LCD is so small and basic.

Sony A850 Main LCD Display Screen Info
1 - Shutter Speed 2 - Exposure Mode 3 - Register Number 4 - Exposure Compensation 5 - Flash Mode 6 - Flash Exposure Compensation 7 - Drive Mode 8 - Focus Mode 9 - Creative Style, Image Parameters 10 - Image Quality 11 - Battery Status 12 - Image Size 13 - Operation Guide	14 - Aperture Value 15 - Exposure 16 - AE Lock 17 - EV Scale 18 - ISO (Sensitivity) 19 - AF Area 20 - D-Range Optimizer 21 - Metering Mode 22 - White Balance 23 - Remaining Shots (Buffer Space) 24 - Memory Card

Large- and Small-Type Options
Sometimes you don't need to see every last detail about the camera's operation, but rather prefer to concentrate on just the most important settings. Like other Sony SLRs, the Sony A850 has two different display options, that apply to both the horizontal and vertical formatted data screens. The large-type/low-density option drops the details on Flash mode, Metering mode, AF mode, Card type, Creative Style, and Contrast, Saturation, Sharpness, Brightness and Zone settings.

Sony A850 Intelligent Preview

The Alpha 900 introduced what Sony calls "Intelligent Preview", which simulates the results of changes in settings in real-time, on an pre-capture image that isn't stored on the memory card. The A850 also offers this feature. It can simulate the effects of white-balance adjustment, exposure, DRO settings, etc. The animation to the right shows the effect on exposure of changing the shutter speed, for example. Some things it can't simulate however is the blurring effect of a slow shutter speed with a moving subject, or the depth-of-field change when adjusting aperture.

Sony A850 Playback Mode Displays

The Playback button on the rear panel accesses Playback mode, where you can review captured images. Pressing the DISP button cycles through displays with information overlay on or off. The Histogram button displays a RGB+L histogram along with recording data and any areas with lost highlights or shadows are illuminated. Pressing the Index button cycles through 25, 9 or 4 frame index views and individual images can be selected using the multi-selector joystick. Images can be zoomed by using the Enlarge button, and magnification can be adjusted up to 19x (depending on image size) using the rear control dial, or a zoom box can be defined using the multi-selector joystick. Enlarged images can also be scrolled in the X or Y direction using the joystick.

Optics

Sony A850 Optics

Alpha lens mount. The Sony A850's Alpha lens mount is compatible with the full array of Alpha lenses, both screw-drive and electronic autofocus models. A crop mode is available for DT lenses designed for APS-C sized sensors, but the manual cautions that exposure accuracy may suffer with DT lenses.

The Sony A850 features a bayonet lens mount, which accommodates a wide range of Sony and Konica-Minolta autofocus lenses. The Sony A850 is sold body-only, so no kit lens is offered. A small button on the front of the camera releases the lens from its mount, so it can be turned and removed.

All current Sony lenses may be used with the A850, but DT (sub-frame) lenses may require exposure adjustments due to the corner darkening produced by their sub-frame image circles. (The camera does support an APS-C exposure mode, that crops a sub-frame area from the larger sensor, but be prepared for possible exposure issues.) All Konica-Minolta AF lenses are compatible with the Sony A850 as well, but note that the 1x-3x Macro Zoom lens isn't compatible with the A850's SteadyShot image stabilization: Turn that feature off when using one of these lenses.

The Sony A850's CMOS sensor is roughly the same size as 35mm film (35.9mm x 24mm), so the angle of view at any given focal length will be the same as on a 35mm camera.

Sony Alpha 850: Autofocus System

The Sony A900 marked a new level of autofocus sophistication for Sony, and the A850 carries over the same AF system. At first glance, the viewfinder might look like a step backwards, as there are fewer AF points visible in the viewfinder than we've seen in previous Sony SLRs like the A700. It turns out though, that there are now two classes of AF points: Nine Primary AF points are marked in the viewfinder and illuminate to show subject acquisition. In addition, 10 new "Supplemental" AF points are arranged between and/or around the Primary points. As their name suggests, the Supplemental AF points assist with autofocus operation, but aren't selectable under user control, and don't illuminate in the viewfinder when they've locked onto a subject. The Sony A850's sensor pattern is shown in the illustration below.

In the diagram above, the blue rectangles with black marks in their centers are the Primary AF points, while the green rectangles mark the Supplemental points. Sony's been a little cryptic about the function of the Supplemental AF points, but the way they surround and fill in between the Primary ones suggest that they can provide additional position and velocity data for dynamic AF tracking.

It's not entirely clear, though, how the two types of AF points interact during autofocus operation: For instance, if the closest/most prominent subject detail falls under a secondary AF point, will it lock focus on it? Or, are the Primary AF points the only ones that can initially lock focus, with the Secondary AF points only helping with subject tracking during continuous AF operation? (Note that the Sony A850's manual points out that the Supplemental AF points are only active in wide-area AF mode.)

When it comes to subject tracking, more AF points are definitely a good thing, as they give the camera's autofocus system a much more comprehensive view of subject distance across the frame. On the other hand, as we've seen in the case of Nikon's D300 and D700 SLR models (which have no less than 51 AF points), a large number of AF points can actually slow shutter response in dynamic-area AF mode.

The cluster of AF points right at the center of the frame is typical of most SLRs, but Sony packs more in than many systems do. There's a "dual cross" array, a group of four sensors that create an expanded area of AF sensitivity, responding to both horizontally- and vertically-oriented subject detail. There's also a single, large, horizontally-oriented sensor that provides significantly greater AF accuracy, but only for lenses having maximum apertures of f/2.8 or larger.

As is often the case with full-frame SLRs though, the Sony A850's AF array covers a bit less of the total frame area than those of the A700 and other Sony sub-frame DSLRs, so subjects will need to be closer to the center to be covered by the AF system.

Sony A850 Autofocus Area Options

Autofocus Area also has three options available through the Function or Record menu: Wide, Spot, and Local (manual setting). The default option is a nine-point Wide Focus area, indicated on the Quick Menu display by an array of dashes inset within four widely-spaced brackets in the viewfinder image. You can override the chosen AF mode by pressing the Spot AF / OK button in the center of the Multi-controller, which defaults to the more accurate center AF point (the latter indicated by a target box in the center of the viewfinder). 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 nine Primary AF points. The active AF area is briefly illuminated in the viewfinder. Like the Sony A900, the A850 includes the ability to apply autofocus micro adjustment, which offers +/-20 step adjustments for up to 30 lenses to address front- and back-focus issues.

Sony A850 Autofocus Modes

The Sony A850 has three main focusing modes, namely Single-shot, Continuous, and Automatic. In single shot mode, focus is set when you initially half-press the shutter button (or trigger focus via the AF/MF button, if you've configured it to act as a focus lock control via the AF/MF option on Custom Settings Menu 1). When focus lock is achieved, a viewfinder indicator illuminates, and the camera beeps to let you know that the subject is in focus. In Wide Area mode, the AF point selected illuminates briefly as well, so you tell what the camera has locked onto.

In single-shot mode, if the subject moves, the focus won't shift to track it. Conversely, in Continuous AF mode, when the shutter button is half-pressed and held, the camera automatically switches to Wide Area AF (if it wasn't already in that mode), and will continuously adjust both the focus setting and its choice of AF points to follow the subject. In this mode though, the selected AF points won't illuminate, and there's no audio signal to let you know when the subject is in focus.

Auto AF mode lets the camera start out in single-shot AF, but then switches to Continuous AF if it detects subject movement after the initial focus lock. When using the A850's continuous shooting option in conjunction with Auto AF mode, the first shot of a series will be captured in single-shot AF mode, but the camera will automatically switch to Continuous AF mode for the second and subsequent frames in the sequence.

Sony A850 AF Assist

Like the A700 and A900, the A850 has a very bright LED built into the body, that projects a pattern onto the subject for better focusing in dim light. The pattern projected by the LED is a significant help when dealing with low-contrast subjects. Thanks to the projected pattern, the Sony A850 can focus on a blank wall in total darkness. (Not that a blank wall would make a particularly interesting subject, but if it can handle that, it can probably handle most any normal subject.)

SteadyShot INSIDE: Sony A850 Anti-Shake

The Sony A850 also employs Sony's SteadyShot INSIDE (their latest branding; previously referred to as Super SteadyShot) anti-shake technology, which uses a highly sensitive angular rotation sensor and Smooth Impact Drive Mechanism (SIDM) to move the sensor assembly itself to counteract camera movement, rather than the conventional approach of moving an optical element inside the lens. This body-based anti-shake approach is based on technology Sony acquired from Konica-Minolta, but Sony claims that it has been improved significantly since that time.

Sony claims that the SteadyShot INSIDE anti-shake system in the A850 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.

When SteadyShot INSIDE is activated, the SteadyShot scale on the right side of the viewfinder display indicates the degree of stabilization. A downside to Sony's body-based SteadyShot approach is that while you can see the results of stabilization on competing lens-based designs, you have only this scale to tell you how the A850's SteadyShot mechanism is doing. SteadyShot minimizes the effect of blurring caused by slight camera movement, which is more noticeable at long focal lengths.

Sony A850 Anti-Dust Technology

To help combat dust particles on the imaging sensor from changing lenses, Sony included both an anti-static coating on the sensor filter and an anti-dust vibration to automatically shake the sensor each time the camera is shut off. The anti-static coating may be of some benefit, but we frankly don't expect much from the A850's vibration cycle: It uses the same motion actuators as the image stabilization system. This means that the peak vibration frequency is probably on the order of a few hundred hertz (cycles per second). That's not nearly fast enough to produce strong enough g-forces to shake loose most dust particles; only the very largest pieces are likely to be dislodged by the SteadyShot system's relatively leisurely vibration. (Other vibration-based dust removal systems use frequencies in the tens of kilohertz: 20,000 to 50,000 cycles per second.)

The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Sony Alpha DSLR-A850 Photo Gallery .

Exposure

Sony A850 Exposure Options

This page will seem very familiar if you've read our Sony A900 review. The only difference is the A850 has a single speed Continuous Mode, while the A900 offered High and Low Speed options.

The Sony A850 offers all the exposure options you'd expect in a high-end prosumer SLR, plus a few Sony-specific options, and some nice increases in control over previous models. Available exposure modes include Program AE, Manual, Aperture Priority, and Shutter Priority modes with shutter speeds from 1/8,000 to 30 seconds available, as well as a Bulb setting for longer exposures. The x-sync speed for flash photography is also an impressive 1/250 second with the SteadyShot image stabilization disabled, or 1/200 second with it activated.

A very nice touch that's common on a lot of SLRs these days, yet welcome nonetheless, is that, while in Program AE mode, you can rotate either the front or rear control dials to select different combinations of aperture and shutter speed settings than those normally chosen by the autoexposure system. (That is, if the automatic program would have chosen 1/125 second and f/5.6, you could instead direct the camera to use 1/60 at f/8 or 1/30 at f/11, to get greater depth of field.) This is a very handy option for those times when you need some measure of increased control, but still want the camera to do most of the work for you. We personally use this capability more than Aperture- or Shutter-priority metering in our own shooting. An added wrinkle in the Sony A850 is that turning the front control dial sets the mode indicator to P_S (program shift/shutter priority), while turning the rear control dial sets the indicator to P_A (program shift/aperture priority), so you can take control of either shutter speed or aperture, letting the camera make the appropriate choice for the other variable.

Another feature that's also pretty common, but still very welcome is the electronic analog exposure display visible in the optical viewfinder data readout as well as on the rear-panel shooting display when the camera is in Manual exposure mode. This shows the amount the camera thinks an image will be over- or underexposed, based on the settings you have selected, and helps you find the best exposure for the subject.

Sony A850 ISO Range
ISO sensitivity ranges from 100 to 6,400, adjustable by pressing the ISO button on the right side of the top panel of the camera and then using the up/down arrow directions of the Multi-Selector, or either the front or rear control dial to select values from those shown on the rear display panel. The front control dial increments the ISO number in one-stop increments (a factor of two between readings), while the rear control dial adjusts in increments of 1/3-stop. The native ISO of the Sony A850's sensor is 200, but an ISO 100 option is available as a range extension for times when you need the slower shutter speeds ISO 100 would provide. Expect poorer tonality at ISO 100 though. Likewise, the maximum "normal" ISO on the A850 is 3,200, but an extended value of 6,400 is available, albeit with significantly higher levels of image noise.

At ISO settings of 1,600 and above, the Sony A850 gives you four choices for high-ISO noise reduction. This setting defaults to Normal; options of Low, High, and Off are also available. - And big kudos to Sony for listening to owners (and reviewers) and letting the Off option actually turn off noise reduction, at least in the RAW files (and apparently in the JPEGs as well). This is a huge benefit for those who want to use third-part noise reduction software on the A850's RAW file output, and brings the A850's RAW files in line with the philosophy of RAW files containing truly "Raw" data. For more discussion of this refer to the Sony A900 Noise Reduction tab of this review.

Sony A850 White Balance Options
White balance modes on the Sony A850 include Auto (usable from roughly 3,000K to 7,500K), Daylight (5,300K), Shade (5,300K), Cloudy (7,500K), Tungsten (2,800K), Fluorescent (no color temperature listed, since fluorescent light spectra don't translate well into Kelvin temperatures), and Flash (6,500K). Direct Kelvin temperature settings are also available, as is a Custom white balance option, for setting white balance from a white or grey card.

In most of the white balance modes, you can fine-tune the color in steps of about 10 mireds. You can use either the left/right arrow directions of the Multi Selector, or the rear control dial to make these adjustments. Adjustments in the + direction make the image more reddish; those in the - direction make it more bluish. We like this feature a lot, as we often wish we could use one of a camera's standard white-balance settings, but tweak it to be just a bit warmer or cooler than the default. To be sure, some experimentation is required to familiarize yourself with the impact of these "tweaked" white balance settings, but having them available is a big plus. In Fluorescent mode, the left/right arrows select between different types of fluorescent lighting, and no fine-tuning is available within each type.

In Kelvin white balance mode, the up/down directions on the Multi Selector adjust the Kelvin temperature, while the left/right directions step through simulated color filters, covering a range equivalent to that from Magenta 9 to Green 9 in the CC (Color Correcting) filter scale. Increments between steps are roughly equivalent to a CC number 5 filter.

As usual, Custom white balance is set by selecting Set from the Custom White Balance dialog screen, pointing the camera at a neutral white or grey card under the lighting you'll be shooting in, and then pressing the shutter button. If the white balance you've captured is good (the camera will warn you if it isn't), you'll be given an option to store it in one of three Custom White Balance registers.

You can also bracket white balance exposures (see the Autobracketing discussion below). Two options are available; Hi which shoots with steps of approximately 20 mireds between shots, or Lo, which shoots with steps of 10 mireds.

Sony A850 Metering Options

The Sony A850 offers three metering modes, selected via the Metering Mode lever on the back of the camera: Multi-segment, Center-Weighted, and Spot. The default Multi-segment metering mode takes readings throughout the image to determine exposure, using an array of 39 hexagonal segments covering the bulk of the frame, and one large 'segment' that covers the rest of the surrounding area. Center-Weighted gives precedence to the center of the image while reading the whole frame. Spot metering, useful for high-contrast subjects, bases the exposure reading on the very center of the image, letting you set the exposure based on a small portion of your subject. You can lock an exposure reading by pressing the AE Lock button on the back panel. Halfway pressing the Shutter button also locks both exposure and focus, but only in autofocus mode.

The A850's Exposure Compensation adjustment increases or reduces the overall exposure from -3 to +3 exposure equivalents (EV) in one-half or one-third step increments, in all exposure modes. An Auto Bracketing feature captures multiple shots with different exposure, white balance, or other parameters: See the section on Bracketing below for more details.

Sony A850 Drive Modes

The Sony A850 offers a variety of shooting modes via the Drive button on the right side of the camera's top panel. Pressing this control brings up the Drive mode setup display on the camera's LCD, after which you can use the left/right and up/down arrows of the Multi Selector or the front and back control dials to make selections. The front control dial steps through the main modes, the rear control dial selects options within each mode.

Drive options include single shot, continuous shooting (note: the A900 offered high and low speed options, but the A850 does not), self timer (options of 2 or 10 seconds), Continuous bracketing, Single Shot bracketing, White Balance bracketing, DRO mode bracketing, Mirror Lockup, and Remote Commander.

Sony A850 Bracketing Options

The Sony A850 offers an unusually wide range of bracketing options. There's of course the exposure bracketing found on most cameras, but the A850 goes a bit further than many. It offers step sizes of 0.3, 0.5, and 0.7 EV with either three or five shots in the bracket, but also offers a step size of 2.0 EV, with three shots in the bracket, for users interested in HDR (High Dynamic Range) photography. The A850 offers separate settings for continuous-mode exposure bracketing or single-shot bracketing. In both modes, the fact that you're bracketing is indicated in the viewfinder by a "br" indication, and by lines above the exposure scale showing what exposure biases are going to be used. In single-shot mode, each line disappears when its corresponding exposure has been captured. (Nice, you always know where you're at in an exposure series, if you get interrupted for any reason.) Bracketing order can be changed via an option on the Setup menu, the default being 0 > - > +, with an option to make it - > 0 - +.

White balance bracketing always involves 3 shots, one at the default white balance setting, one with the white balance "tweak" set to a more blue color cast, one with it set to a more reddish color cast. The WB Lo bracket option uses step sizes of 10 mireds, the WB Hi option uses steps of 20 mireds. White balance bracketing occurs only in single-shot mode, and there's no indication in the viewfinder where you are in the sequence. (That we could see, anyway.) The white balance bracketing is a nice feature, but we'd like to see more options for step size and (particularly) number of shots in the series. It'd be nice to be able to shoot a bracket of 5 shots in situations with tricky lighting. (And would be nice to do it in continuous drive mode too - see the parenthetical note two paragraphs down.)

The A850 also lets you bracket the effects of the Dynamic Range Optimizer (DRO) function, in three steps. As with the WB bracketing, Hi and Lo options provide greater or lesser amounts of bracketing, but it isn't clear how the steps compare to the manual adjustments available via the Quick Menu. As with WB bracketing, DRO bracketing is only available in single step mode, and there's no indication of where you are in the sequence.

(As a side note, we really wish that the single/continuous option could somehow be set up in parallel with WB and DRO bracketing: It'd be so much easier if you could just press the shutter and have the camera fire off 3 shots. Some cameras set bracketing separately from drive mode; we think that's the right way to do it: Let the user decide whether they want to shoot continuously or one shot at a time separately from the type of bracketing they're wanting to do.)White balance bracketing can occur in the same 3 or 5-shot brackets, with the step size between shots being either 1, 2, or 3 of the white balance "fine tuning" steps. (As noted above, each such step corresponds to 10 mireds of color-temperature adjustment except when in Fluorescent mode, which offers larger steps.) Normal white balance bracketing can thus cover a range from +/- 10 mireds (3 shots, 1 step each ) to +/- 60 mireds (5 shots, 3 steps of variation each).

Sony A850 Creative Style Options

The Creative Style menu has been a fixture on Sony SLRs for a while now, but the A850 takes the feature a couple of steps forward. The Creative Style option found on either the Quick menu (accessed via the Fn button and multi selector, or via the C (custom) button if the Creative Style menu has been assigned to it) or on the first screen of the Record menus offers a selection of presets for varying subjects, including Standard (faithful color reproduction), Vivid (increased contrast, saturation and sharpness), Neutral (reduced contrast and saturation), Portrait (optimized skin tones), Landscape (optimized daytime outdoor scenery), and Black & White.

The six options just mentioned are available by default in the main Creative Style list. There are another seven options though, that can be swapped in for any of the six defaults. The screen shot at right shows this being done, the "Clear" style being substituted for the Standard one. With the Creative Style menu up, you can use either the multi selector or the control dials to move right (selecting the name of the style at the bottom of the right pane), then move up or down to step through the full list of creative styles available. Exit the Creative Style menu or just press the shutter button, and whatever choice was selected will remain.

The full list of Creative Styles is quite extensive. Besides the six named above, there are Clear (for "capturing images in a clear tone with limpid colors, suitable for capturing radiant light"), Deep (for "capturing images with deep and dense color expressions"), Light (for "capturing images with bright and uncomplicated color expressions, suited to capturing refreshingly light ambience"), Sunset (emphasizing the red colors of sunsets), Night View (reducing contrast to render night scenes more faithfully to the way our eyes see them), Autumn Leaves (highlighting red and yellow tones), and Sepia (monochrome, but with a brownish "sepia" color cast).

Within each Creative Style, you can adjust a number of imaging parameters, including contrast, saturation, sharpness, brightness, and something Sony calls "Zone". All the options seem pretty self-explanatory, but Zone is a little odd, and Sony doesn't give much of an explanation. The range of settings for Zone run from -1 to +2. It seems that Zone adjusts the A850's tone curve: Higher settings shift the image's histogram to the left, to prevent overexposure of highlights, while lower numbers seem to push it to the right, to prevent shadows from plugging.

Interesting to note is the way the Sony A850 lets you arbitrarily assign Creative Style options to the 6 preset "slots" is that you can have more than one of the slots occupied with the same basic preset, but with different tweaks applied to it. For instance, you could have two versions of Standard programmed into slots 1 and 2, with the first being the camera's default, but the second having contrast and saturation boosted one notch each, and sharpness dialed down. This makes it easy to create a number of different presets that uniquely suit your shooting style and subject matter, and be able to switch between them rapidly while shooting.

The images above were taken from our standardized test shots. For a collection of more pictorial photos, see our Sony Alpha DSLR-A850 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 DSLR-A850 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 A850 Performance

Imaging

Sony A850 Image Quality

Color

Saturation & Hue Accuracy
Accurate color 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. At its default settings, the Sony A850 pushes strong reds, oranges, greens and blues just a little, but actually undersaturates bright yellows, some greens, and cyan tones very slightly. Overall, saturation levels are very good, just slightly higher than the A900's default response, perhaps therefore more appealing to consumer photographers. Most 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, with the color balanced properly for the light source, the Alpha A850's skin tones looked natural, but perhaps just slightly on the warm side. 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 Alpha 850 showed only a few small color shifts relative to the correct mathematical translation of colors in its subjects, but had very good accuracy overall. Most noticeable was a shift in reds toward orange, and yellow toward green, with some shifts in cyans and blues as well, but overall hue accuracy was very good. Hue is "what color" the color is.

Saturation Adjustment
The Sony A850 has a total of seven saturation settings available (only five are shown below), 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. (So if you find the A850's default color rendering a little understated for your tastes, it will be quite easy to boost it one or two notches to better match your personal preferences.)

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

The table above shows results with several saturation settings, see the Thumbnails index page for more (look for the files named A850OUTBSATx.JPG). Click on any thumbnail above to see the full-sized image.

Sensor

Exposure and White Balance

Indoors, incandescent lighting
Good color with both the Manual and 2,600 Kelvin white balance settings, but very warm results with Auto and slightly warm with Incandescent. Above average positive exposure compensation required.

Indoors, under normal incandescent lighting, the Sony Alpha 850 produced very warm color with its Auto white balance setting. (This isn't the first camera we've said this about: We expect better automatic white balance handling in a high-end camera.) The Incandescent setting wasn't too far off the mark; just warm enough to suggest the color of the original light source, without seeming overdone. Both the Manual and 2,600-degree Kelvin settings produced more accurate results. It was a bit of a toss-up between them, as the Manual setting was a hint warm and the Kelvin option was a bit cool. The +1.0 EV positive exposure compensation required for this shot was higher than average. (This indoor scene usually requires about +0.3 EV exposure compensation.) Color looks good throughout the frame, with only the slightest purplish tints in the blue flowers. (Many digital cameras reproduce these flowers with a dark, purplish tint, so the Alpha 850 actually performs a little better than average here.) 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 color.

Outdoors, the Sony Alpha A850 performed well, but at its default contrast setting required +1.3 EV exposure compensation for the Portrait to avoid rendering the model's face too dark. Even with that much positive exposure compensation though, the A850 did a surprisingly good job of holding onto highlight detail: While the highlights in the mannequin's shirt will appear blown on many computer monitors, close inspection in Photoshop or other editing software reveals that very few areas are actually blown out. Most of the clipping occurs with specific colors in the flowers and brooch. Despite the high contrast (as you might expect under such harsh lighting), the camera did a better than average job of holding onto detail in both the deep shadows and bright highlights. The Sony A850 did a pretty good job of exposing the House shot without any exposure compensation, and managed not to blow out many highlights or lose much shadow detail in the process. Color balance is good as well, with good saturation considering the bright lighting. The camera's contrast adjustment did a very nice job of toning down the exposure without creating any strong color variations in the skin (though skin tone does change slightly - see the "Extremes" heading below for samples). Overall, a very good performance.

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

Resolution
Extremely high resolution, about 2,150 lines of strong detail.

Our laboratory resolution chart revealed sharp, distinct line patterns down to about 2,150 lines per picture height in the horizontal direction as well as in the vertical direction. Complete extinction didn't occur until about 4,000 lines per picture height in the horizontal direction and about 3,600 lines in the vertical direction. 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
Sharp, very detailed images, though minor edge-enhancement artifacts visible on high-contrast subjects. Minor noise suppression visible at low ISO.

Sharpness. The Sony Alpha 850 produced amazingly detailed images, with good sharpness. Some slight edge enhancement artifacts are visible on high-contrast subjects such as the crop above left, but overall results are still very good. We did notice A850 images seemed slightly softer overall than those from A900 at the default settings. We'll need to wait for third-party RAW converter support to see if that's due to a stronger anti-alias filter, or just differences in default processing or noise reduction. 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 only minor noise suppression artifacts, as the darker areas of the model's hair show a lot of detail. Individual strands are still distinguishable even in the lighter shadows, though they begin to merge as shadows deepen. Still, good performance here, especially considering the 25-megapixel sensor and the resulting smallish pixels. 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 of this writing (August 27, 2009), our usual third-party RAW converters (Adobe Camera Raw and dcraw) do not support A850 .ARW RAW files. We'll come back to update this section when they do.

ISO & Noise Performance
Fairly low noise at ISO 100 through 400. Effects of noise reduction impacts fine detail at higher ISOs.

The Sony Alpha A850 produced fairly low noise at its lower sensitivity settings, however we start to see some slight smudging and loss of detail already at ISOs as low as 400. As you'd expect, noise and loss of detail becomes more apparent at ISO 800, with noise "grain" becoming increasingly courser, increased blurring of fine detail and some chroma noise in the shadows. At ISO 1,600, along with increased detail loss, the chroma noise becomes more obvious and no longer relegated to just deep shadows. ISO 3,200 continues this trend with even more detail loss and blotchiness, and ISO 6,400 is quite noisy with chroma noise and blurring almost entirely obliterating fine detail. There is also a slight desaturation of images at ISOs 3,200 and 6,400. Keep in mind that these are 25-megapixel files, though, so detail loss won't be nearly as apparent at normal print sizes. See the Print Quality section to find out what the recommended maximum size print is at each ISO setting.

Note: While high ISO image quality appears to be identical to that of the A900 (or very nearly so), we encountered some focus variation between shots with the A850 on this target that we didn't with the A900. As a result, we ended up using manual focus with some careful distance bracketing to insure sharp images for the above ISO series. The identical lens was used on both cameras, so the difference in focus behavior shouldn't be the result of any sort of a lens issue. Sony didn't mention any change to the A900's AF system for the A850 when they briefed us, so we're not sure why it had some difficulty with this scene.

Extremes: Sunlit and low light tests
High resolution and good shadow detail. Good low-light performance, capable of capturing bright images in near darkness.

Sunlight. The Sony Alpha A850 handled the deliberately harsh lighting in the test above pretty well. Though contrast is a little high, highlight detail is good and shadow detail very good. The camera's contrast adjustment also did a good job of decreasing overall contrast without introducing significant color or saturation variations. A higher-than-average +1.3 EV exposure compensation was required to keep the model's face from looking too dark, as the +1.0 EV exposure was a touch too dim. This resulted in a few lost highlights in the model's shirt, brooch and in some of the flowers, but not as much as we're accustomed to seeing. Be sure to use fill flash in situations like the one shown above; it's better to shoot in the shade when possible.

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.)

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 A850's contrast setting meets both challenges.

Minimum Contrast, normal D-R setting (Off)
Contrast set to lowest, +1.0 EV	Contrast set to lowest, Auto Exposure

At its lowest contrast setting, the A850 did an excellent job of preserving highlight detail, maintaining natural-looking skin tones, and holding nice detail in the shadows. The A850 captures good color outdoors, albeit just slightly on the warm side. Overall, very good results here, especially when the contrast setting is tweaked.

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

The series of shots above shows results with several different contrast adjustment settings, showing the minimum step size around the default, as well as both extremes. While you can see the extremes, it's hard to really evaluate contrast on small thumbnails like these: 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.

Sony's DRO (Dynamic Range Optimization)
Sony's Dynamic Range Optimization system analyzes the range of brightness of each image, and adjusts the camera's image processing parameters accordingly, to try make the best use of the available dynamic range. Three options are available on the A850: DRO Off, Standard DRO, and Advanced DRO+. Unlike lesser Sony SLRs, the A850's default for DRO is Off. The A850 also allows you choose the strength for the Advanced DRO+ effect, from level 1 to 5. Standard DRO looks at the entire image and effectively adjusts contrast and brightness across the entire image for best effect. Advanced DRO+ analyzes everything, but makes local adjustments to bring out shadow detail and preserve highlights. The Level 1 through 5 settings for DRO+ generally all seem to have a stronger effect than does the Auto setting, although in this instance, DRO+ Level 1 was close.

DRO Examples
DRO Off	DRO Standard	DRO+ Advanced Auto	DRO+ Advanced Level 5
Highlights
Shadows

The crops above show the results of three DRO settings. Like the A900, by default, the Sony A850 shoots with DRO set to Off. As you can see, DRO Standard which adjusts the overall image boosted both the highlights and shadows, resulted in even more clipped highlights than with DRO set to Off. DRO+ Advanced was able to preserved some highlights, while still boosting shadows a bit (compared to DRO Off). DRO+ Advanced Level 5 is the extreme setting, which did a pretty good job at preserving highlights while at the same time, giving shadows quite a boost. Overall, we liked the DRO+ Advanced Auto setting the best for this shot, as it was able to preserve highlights while opening up the shadows a bit without flattening the image too much. DRO+ Advanced Level 1 (not shown) produced very similar results.

	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
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
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
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
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
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
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
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

Low light. The Sony A850 performed well on the low-light test, capturing usable images at the lowest light level even at the lowest sensitivity setting (ISO 100). The A850's metering system struggled a bit at lower light levels though, so we used manual exposure mode to get consistently exposed images for the above table. Automatic white balance however worked quite well, producing a fairly neutral color balance even at high ISOs in very low light. Noise was fairly low up to ISO 400, but as expected, became more noticeable with higher ISOs, especially with noise reduction turned off. There were also some hot pixels visible at high ISOs and low light levels, but we didn't notice any signs of banding. The camera's autofocus system did better in low light than its metering system, as it was able to focus on the subject down to below the 1/16 foot-candle light level unassisted (and in complete darkness with the AF assist enabled). Keep in mind that the longer shutter speeds here demand the use of a tripod to prevent any blurring from camera movement. (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.)

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.) Digital SLRs like the Sony A850 do much better than point & shoots, but you still shouldn't expect a quick autofocus lock with moving subjects.

Output Quality

Print Quality
Great print quality, good color, sharp 20x30-inch prints from RAW files, usable ones from in-camera JPEGs.

As we noted earlier, the Sony A850's images seemed just slightly softer overall than those from the A900, but the difference was really pretty microscopic, and the A850's printed output was still very impressive. As of this writing (August 27, 2009), our standard RAW converters (Adobe Camera RAW and dcraw) didn't support the A850's RAW files, so we couldn't evaluate how much more detail we could wring from RAW than JPEG. It seems likely, though, that a good RAW converter will be able to deliver quite a bit more detail than that found in its JPEGs, as that was also the case with the very similar A900.

That said, while images printed at 20 x 30 inches from its JPEGs were a little soft-looking, they weren't bad - Certainly good enough for wall display, even if people were to get up fairly close and squint at them.

Checking print quality at higher ISOs, we found results very similar to those if the A900: The Sony A850's images produced good-looking 13x19 inch prints up to about ISO 400 or 800: Minor chroma noise began to appear at ISO 400, and became more prominent at ISO 800, although many users would probably find the ISO 800 results at 13x19 inches suitable for wall display. At 5x7 inches, images looked good to ISO 1,600 and usable to ISO 3,200. (As noted elsewhere, the Sony A850 is a camera you'll buy for its outstanding resolution, not its high-ISO capability.)

Color-wise, we found the Sony A850's images very appealing. As we noted in our Imatest results, its color is just slightly more saturated than that of the A900, but not at all to the point that it looks overdone. We think most photographers would find the Sony A850's color appealing.

Bottom line, the Sony A850 is a camera that delivers incredible resolution under good to moderate lighting, and as such should work well for commercial work, portraits, landscapes, architectural and fine art photography and similar applications. At the highest magnifications though, some noise is visible even at its default ISO 200 sensitivity, and this steadily increases as you go up the ISO scale. As always, the obtrusiveness of its image noise varies inversely with the size of the print you're making. If all you care about is 8x11 output, you'll likely find the Sony A850 usable up to ISO 1,600 and possibly higher. On the other hand, we expect that a large part of the reason many people will be attracted to this camera is because they want to exploit its extraordinary resolution by making really large prints. If that's your application, then the maximum useful ISO drops quite a bit, to the extent that ISO 800 is really pushing it, even for 13x19 inch prints. We say "even for 13x19 inch prints" because, while that size is about as large as most prosumer inkjet printers go, it's not all that big compared to the A850's 25 megapixel resolution. (At 300 pixels/inch, the A850's output would measure 13.4x20.2 inches.)

While we haven't been able to test one, a good third-party RAW converter and aftermarket noise-processing software package could give you considerably more ISO headroom. Barring that, the A850 is really best used at ISO 400 and under, at least for those times when you'll want to print larger than 13x19 inches.

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 on the (older) Canon iP5200 here in the office. (See the Canon Pixma Pro9000 Mark II review for details on that model.)

Viewfinder

Sony A850 Viewfinder

The Sony A850 is of course, an SLR, so the optical viewfinder offers a true, through-the-lens display. A dioptric adjustment dial accommodates eyeglass wearers, letting them adjust the viewfinder optics between -3.0 and +1.0 diopters. Specified at 20mm from the eyepiece, the eyepoint is good, but not quite as high as those of some other cameras, so eyeglass-wearer Dave found he had to press the lenses of his glasses pretty firmly against the A850's eyecup in order to see the full frame area.

If you're accustomed to shooting with sub-frame SLRs, the first thing you'll notice when looking into the Sony A850's viewfinder is how huge it is. When we first shot with it, one of the Sony staff in attendance joked that we'd need to hold onto the edges of the viewfinder bezel, to keep from falling into it: He wasn't far wrong. Viewfinder specifications commonly include things like eyepoint height and magnification ratio, but don't address how much of your apparent field of view the viewfinder image covers. If they did, the A850 would come out somewhere very high on the list. In practice, a much larger viewfinder like this does a lot to connect you with your subjects: You have much more of a sense of just looking at the subjects, rather than peering down a tunnel at them.

In terms of specs, the Sony A850's viewfinder has an optical magnification of 0.74x when using it with a 50mm lens focused at infinity and the dioptric adjustment set to -1 diopter. This is the same magnification as the A350's viewfinder, a bit more than that of the Nikon D700 (0.72x), a bit less than that of the Canon EOS-1Ds Mark III (0.76x). What the viewfinder magnification factor means in practice is that objects seen through the Sony A850's viewfinder when using a 50mm lens will be about 74% as large as they'd appear to your unaided eye; with a 70mm lens, they'd appear just slightly larger than normal size. The benefit of having a high magnification number is that it makes it easier to shoot with both eyes open, as the view through the viewfinder will be close to what your other eye is seeing, unaided. Having both eyes open when shooting greatly improves your situational awareness, making it much easier to acquire and track quickly moving objects. At least for lenses in the roughly 50 - 90 mm focal length range, the Sony A850 makes two-eyed shooting relatively easy.

Besides the huge view it gives you, the Sony A850's viewfinder also sports two other desirable characteristics. First, the 100% internal reflection of its true pentaprism optical design makes for a very bright image. Secondly, the A850's viewfinder offers 98% frame coverage, (down slightly from the A900's claimed 100% coverage) making it easy to frame subjects quite precisely. (Our lab measurement put the Sony A850's viewfinder accuracy at just about 98% on our test sample, matching Sony's claim.)

Like the A900, the A850 has a built-in eyepiece shutter, actuated by a lever to the left of the eyepiece. This is used to block light from interfering with the exposure metering when the viewfinder is not being used (ie., on a tripod in self-timer mode).

Sony A850 Viewfinder Information Display

The illustration above shows the information that's displayed in the Sony A850's optical viewfinder. It's identical to the A900. There are the usual autofocus area markers, but also marks that delineate the 16:9 aspect ratio shooting area and the corners of the APS-C shooting area, for when you're running the camera in that mode, when using a sub-frame lens.

Along the bottom of the display are the usual indicators for shutter speed, aperture, exposure compensation and shots remaining in continuous mode. There's an unusual number of indicators associated with flash operation, thanks to the sophistication of Sony's flash offerings. There's the usual flash exposure compensation and flash-charging indicators, but also icons showing wireless flash (WL) and high-speed sync (H) operation. Since the Sony A850 has no internal flash, all flash functions require the use of an external flash, with a number of Sony models to choose from. To use the wireless flash triggering and control option, you need to have one of the top-end HVL-58AM models mounted on the camera to control the remote units, but all currently-manufactured Sony flash units can work as wireless remotes. All current Sony flash units are also capable of high-speed (also called "FP") synchronization, allowing flash exposures at any shutter speed the camera is capable of.

There's one additional indicator in the Sony A850's viewfinder that we particularly like: In the lower right-hand corner, there's what amounts to a little bar graph that's active whenever the SteadyShot image stabilization is in use. This shows how much camera shake the SteadyShot system is currently seeing. By waiting for the fewest bars to be displayed, you can pick a moment when shake is at its minimum, giving the SteadyShot system the best chance at completely compensating for it. This strikes us as quite handy, and is a feature we wish were available with lens-based IS systems. We'd wager that intelligent use of this display could add a good stop or so to minimum shooting speed, and could help the effective performance of the Sony A850's IS system.

User-Interchangeable Focusing Screens

While some previous Sony DSLR models had interchangeable focusing screens, this has always in the past been an option that could only be performed by a Sony service center. The reason for this was that the camera's exposure system would have to be adjusted for the focusing screen being swapped in. In the Sony A850 though, a Focusing Screen option on the Setup menu lets you specify which screen is in use, so the camera can adjust its exposure metering as needed.

There are three different focusing screens available for the Sony A850:

• Type G - The default screen, a good trade-off between brightness and focus discrimination
  
  
• Type M - A "Super Spherical Acute Matte" screen. This screen provides much sharper discrimination between in-focus and out-of-focus conditions, but at the cost of some brightness. It's only intended for use with lenses having maximum apertures of f/2.8 or greater.
  
  
• Type L - This screen is the same brightness as the default Type G type, but provides a grid to help with horizontal/vertical alignment or rule-of-thirds composition.

Viewfinder Test Results

Coverage
Good accuracy from the optical viewfinder. The A850 does not support Live View on the LCD.

The Sony Alpha A850's optical viewfinder showed about 98 percent coverage accuracy with our Sigma 70mm f/2.8 prime lens, matching Sony's claim of 98 percent accuracy. This is good for a semi-pro digital SLR, and matches Sony's specification. (Note that we measured about 99% coverage for the A900 with the same lens, so the difference is not that great.) Sony chose not to offer a Live View mode on the A850, since Sony's Live View system would have required a smaller, dimmer pentamirror design.

Flash

Sony A850 Flash

Thanks to its huge pentaprism, the Sony A850 has no built-in flash. (Sony felt it simply would have added too much bulk to an already large bulge on the camera's top. Plus, with some of the large full-frame lenses is likely A850 to be used with, a built-in flash would be bound to have problems with shadowing.) So the only option for flash on the Sony A850 is an external unit.

In that, you'll largely be restricted to Sony-brand flashes, at least if you want an intelligent flash that interacts with the camera's exposure system. (Although there are third-party units offering varying degrees of compatibility.) The Sony flash shoe is a proprietary design unlike the common hot shoe seen on other camera brands.

The good news though, is that Sony offers a good range of dedicated flash units, from the top of the line HVL-F58AM (seen at right, mounted on top of the A900) down to the entry-level HVL-F36AM (still not cheap at $199 list). Even better news is that all current Sony flash units have wireless capability, so you can combine them into complex lighting setups, with multiple off-camera flashes all controlled from the camera.

One of the more interesting design aspects of the new HVL-F58AM deserves mention. The heads on most external flash units tilt up and down for bounce operation off the ceiling for even illumination and also swivel to let you bounce the flash off a side or back wall for special lighting effects. But what about when you're holding the camera in portrait (vertical) orientation? The head that would previously tilt up to bounce off the ceiling will now only point to the side. You might be able to swivel it to point back up at the ceiling, but your control over the bounce angle won't be as good as when in normal landscape mode.

As shown above, the new Sony HVL-F58AM swivels in an entirely different way, with the whole head rotating in a plane parallel to the back of the camera. This lets it work the same way for normal ceiling-bounce operation, regardless of whether the camera is in landscape or portrait mode. Slick! (We expect to see other flashes copy this design at some point.)

High ISO Noise Reduction

Sony A850 High ISO Image Quality

The Sony A850 offers four high-ISO noise-reduction settings, allowing you quite a bit of flexibility in choosing how you want to make the trade-off between subject detail and noise levels. Sony tells us that the "OFF" setting eliminates all inter-pixel NR processing, but the per-pixel NR that occurs on the sensor itself is always active. (See the Sony A900 Noise Reduction tab of this review for a detailed discussion of the two types of noise reduction processing.) We won't be able to independently confirm that the OFF setting really does turn off the High-ISO NR in the A850's RAW files until third-party RAW processing software is available that can process these files.

See for yourself how the noise reduction works under daylight lighting. Click on any of the crops below to see the corresponding full-sized image. Note that the A850 only starts applying High ISO NR at ISO 1,600, but we have included crops from lower ISOs as a reference.

Sony A850 ISO Noise Comparison Simulated Daylight (Note that High ISO Noise Reduction does not apply to this range)
ISO 100	ISO 200	ISO 400	ISO 800

The above table shows noise and detail levels at ISO 100 through 800, where the Sony A850 does not apply any High ISO Noise Reduction.

Sony A850 High ISO Noise Reduction Comparison Simulated Daylight
	High ISO Noise Reduction Setting
	HINR=Off	HINR=Low	HINR=Normal	HINR=High
I S O 1 6 0 0
	HINR=Off	HINR=Low	HINR=Normal	HINR=High
I S O 3 2 0 0
	HINR=Off	HINR=Low	HINR=Normal	HINR=High
I S O 6 4 0 0

The above crops show the effects of the four levels of High ISO Noise Reduction available on the Sony A850. Discussions with Sony engineers suggest that the "OFF" setting for High ISO NR does in fact disable all inter-pixel NR processing. As discussed on the Sony A900 Noise Reduction tab, the per-pixel NR processing is still applied.

Sony A850 High ISO compared to Canon 5D Mark II Simulated Daylight
	Sony A850		Canon 5D Mark II
	High ISO Noise Reduction Setting
	HINR=Off	HINR=Normal	HINR=Off	HINR=Normal
I S O 8 0 0		n/a - no High ISO NR applied
		n/a - no High ISO NR applied
		n/a - no High ISO NR applied
	Sony A850		Canon 5D Mark II
	HINR=Off	HINR=Normal	HINR=Off	HINR=Normal
I S O 1 6 0 0
	Sony A850		Canon 5D Mark II
	HINR=Off	HINR=Normal	HINR=Off	HINR=Normal
I S O 3 2 0 0
	Sony A850		Canon 5D Mark II
	HINR=Off	HINR=Normal	HINR=Off	HINR=Normal
I S O 6 4 0 0

The crops above compare the Sony A850's JPEG High ISO performance (ISO 800 through 6,400) to that of the Canon EOS 5D Mark II, the A850's closest rival. The Sony A850 may have bested it in terms of number of pixels, and seems to maintain an edge at low ISOs, but it's clear that the 5D Mark II clearly leads when it comes to high ISO performance. (Note that the Sony A850 doesn't offer ISOs 12,800 or 25,600, as does the 5D Mark II, hence no comparisons at those ISO levels.)

Imatest Results

Sony A850 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 A850:

sRGB Accuracy Comparison
Sony A850	Canon EOS 5D II	Nikon D700	Nikon D3X	Sony A900

Interestingly, despite it supposedly having identical "guts" to the A900, it's clear that the image processing of the Sony A850 has been tweaked slightly. Like the Sony A900, the A850 showed very good color accuracy overall. Hue accuracy actually somewhat improved over that of the A900, with most of the hue shift occurring in the cyans, sky blues, reds and oranges. Average saturation was a bit higher in the A900, at 110% (oversaturated by 10% vs 5% for the A900, mostly in the deep blues and reds and some greens). Average "delta-C" color error was a bit better than the A900 though, at 4.78 for the A850 vs 5.27 after correction for saturation. All in all, a very good color response for an SLR, with the saturation boost likely to increase its appeal to consumer users. Mouse over the links below the illustration above to compare results with competing models.

Adobe RGB Accuracy Comparison
Sony A850	Canon EOS 5D II	Nikon D700	Nikon D3X	Sony A900

Using the Adobe RGB color space (which provides a much wider gamut, or range of colors that can be expressed), the Sony A900 delivers more highly saturated color, with an average saturation of 112.9% and average saturation-corrected hue error of 4.7 "delta-C" units, which in this case is actually slightly more accurate than any of the competition. Again, mouse over the links below the illustration above to compare results with competing models. (Note that a slight change in the axes scales for this plot in the most recent version of Imatest results in minor displacements in the dots for both the "Ideal" and "Camera" data.)

This image shows how the Sony A900 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 A850's very good hue accuracy, as well as a gamma curve that results in an overexposure of some colors, notably blues, cyans, reds, orange and some greens. (We've seen this in most cameras we test, increasing the "punch" of images by brightening saturated colors a little, while actually keeping both the hue and saturation level very close to technically accurate values.)

There's a lot in this particular graph, a lot more than we have room to go into here. (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 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.

Here, we see the results at ISO 100, which is as a low extension of the normal ISO range for the A850. The luminance curve is very flat (meaning luminance noise is very fine-grained), however the color channels, particularly the red and blue, exhibit higher noise values, especially at lower frequencies. This graph reinforces our own visual observations of the A850's images, in which we saw that the luminance noise was relatively low, but that the chroma noise was much higher. It's interesting that the "spikes" in the noise spectrum that we normally see from Sony's JPEG processing don't appear to be present with the A850, so perhaps Sony's engineers have tweaked the JPEG encoder a bit.

Here again, Sony has clearly adjusted the image processing of the A850 vs that of the A900: Noise levels in the deepest shadows are somewhat higher than we was with the A900, but noise in the upper shadows through midtones is lower. The spectral energy of the blue and red channel noise is also higher in the lower frequency ranges than in the A900.

Here are the results at the A850's base ISO of 200. Again, the luminance curve is quite flat and the A850 does a good job of keeping plenty of the noise energy at high frequencies. The green channel follows the luminance channel more closely than at ISO 100, but the red and blue channels still show quite a bit more noise energy at lower frequencies than they did in the A900. Likewise, there's more noise in the darkest shadows, but less in the more visible parts of the tone curve. Bottom line, the Sony A850 overall noise levels are low at low ISO, with a frequency spectrum that has more energy on the higher frequency (right-hand) side of the curve in the green and luminance signals than do many cameras, but less so in the red. and blue.

Above is the same set of noise data at ISO 3,200. Here, the Noise Spectrum graph has a dramatic shift toward the left-hand, lower-frequency side than at ISO 200, coarsening the "grain" of the image noise patterns. The red channel also continues to have dramatically more noise energy at lower frequencies than the others. This can be seen in the A850's ISO 3,200 images as very noticeable blotches of chroma noise.

Interestingly, at ISO 3,200, the A850's noise spectrum and noise profile in primary colors (the upper right-hand plot of the group) are virtually identical to those of the A900; much more so than was the case at lower ISO settings.

Here's the same set of noise data at ISO 6,400. Very similar to ISO 3,200, with slightly more shift to the left indicating even coarser "grain" caused by the A850's noise reduction attempts to blur out the noise. Again, the red channel continues to have much more noise energy at lower frequency than the others. Here, we can also see hints of the spectral noise-frequency spikes previously mentioned.

This chart compares the Sony A850's noise performance over a range of ISOs against that of other current, full frame cameras, using default settings. 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. Also, this is a plot of luminance magnitudes, where the A850 does relatively well: A plot of chrominance noise would tell a different story. As you can see the A850's graph tracks the A900 very closely, as you'd expect. The magnitude of their image noise starts out slightly above most of the competition at ISO 100, and remains higher at all ISOs until the Sonys' high ISO noise reduction kicks in more aggressively at ISO 1,600. This brings the curve back down to the Sonys' ISO 800 level, and in-line with most of the competition, but a bit higher than the Canon 5D Mark II. There's quite a large difference at ISO 6,400, but still a pretty good performance for a camera with 24 megapixels. Keep in mind these are at default settings, so the shape and positions of the curves will be influenced by your settings.

Sony A900 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 A900 with a nominally-exposed density step target (Stouffer 4110), and the A900's settings at their default positions, where Dynamic Range Optimization is set to Off.

These are good results for in-camera JPEGs, almost identical to the Sony A900, but not as good as recent results from other manufacturers. The tone curve shows excellent gradation in highlights, but the shadow end trails off a bit more abruptly. Noise levels are a little lower than the A900, either indicating Sony has tweaked JPEG processing, or perhaps it's just sample variation. Again, interesting that the "spikes" have reappeared in the noise spectrum plot at lower right.

Interestingly, the results with DRO set to Off were slightly better at the highest quality level (7.31 f-stops), however overall dynamic range improved very slightly to 10.7 f-stops. This is likely due to the fact that DRO standard increases shadow levels, which also makes noise slightly more evident, knocking the highest quality level down a bit to 7.3 f-stops.

Selecting DRO Plus (Auto) didn't have much of a result on the dynamic range numbers either. We tried some manual DRO levels (1, 3 and 5), but all resulted in reduced Imatest scores with tone curves that had a hump in the midtones.

We normally also analyze RAW files converted with Adobe Camera Raw to better see what dynamic range the sensor is capable of, but ACR does not yet support the Sony A850 at the time of this writing (late August 2009). Using another RAW converter would yield results that aren't directly comparable, so we'll try to update this section after Adobe adds support for the A850's RAW files.

Dynamic Range, the bottom line:

As expected, the Sony A850's results were almost dead-identical to the A900's, with JPEGs placing a bit below those from most other DSLR models we've tested recently. We expect results from ACR processed RAW files will be much better, just as they were with the A900: Despite its lackluster JPEG performance, the A900's dynamic range was among the best we'd measured to date, when processing images from its RAW files. (Note that we measure dynamic range for each camera using its base ISO: This might place some cameras like the A850/900 with base ISOs of 200 at a slight disadvantage relative to those with lower base ISOs.)

To get some perspective, here's a summary of the Sony A850'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.):

The results shown in the table are interesting. One of the first things that struck me when I (Dave) initially looked at test data for a wide range of DSLRs, was that here again, purely analytical measurements don't necessarily correlate all that well with actual photographic experience. There's no question that the Fuji S3 Pro once deserved its place atop the list, as its unique "SR" technology did indeed deliver a very obvious improvement in tonal range in the highlight portion of the tonal scale relative to competing models of its day. (Amazing that it's now surpassed by even consumer-level models using today's technology.) I was also surprised to see the analytical results place the original Olympus E-300 as highly as they did, given that our sense of that camera's images was that they were in fact noisier than those of many other DSLRs that we looked at. In the other direction, I was quite surprised to see the Nikon D2x place as low on the listings as it did, given that we found that camera's shadow detail to be little short of amazing.

One thing that's going on here though, is that we test each camera at its base ISO setting, which should produce best-case noise levels. This is in fact what many photographers will be most interested in, but it does perhaps place some of the Nikons (like the D40) and the Sony A850/900 at a disadvantage, as their lowest ISO setting is 200, as compared to the ISO 100 settings available on most other models.

Sony A900 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 I focus on here. The uncorrected resolution figures are 2,919 line widths per picture height in the horizontal direction (corresponding to the vertically-oriented edge), and 2,840 lines along the vertical axis (corresponding to the horizontally-oriented edge), for a combined average of 2,689 LW/PH. Correcting to a "standardized" sharpening with a one-pixel radius increased both vertical and horizontal resolution, resulting in an average of 2,941 LW/PH. While good, this is slightly below the A900's corrected score of 3,397 LW/PH.

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 unlike the A900, the A850 applies sharpening in the horizontal direction that Imatest considers close to ideal. While Imatest may consider this "ideal," the effect of the sharpening operator extends a fair distance away from the edge itself (close to 3 pixels, based on the graph below), which will tend to blur the finest detail. (As always, you're better off dialing down the in-camera sharpening and applying your own sharpening after the fact in Photoshop or other image-processing software.)

Imatest reports that the vertical direction (horizontal edge) is undersharpened by 6.96%, but in our view, it's actually much more what you'd want to come out of a high-resolution camera like the Sony A850. The Sony A850's images respond fairly well to tight sharpening in Photoshop, but sharpening results will be better in scenes with natural textures than those with abrupt edges (as with text on signs, building features in architectural shots etc), where you'll quickly find halos around high-contrast objects. For optimum results with post-capture sharpening, best to shoot with the in-camera sharpening turned down or (better yet) work from RAW with a good RAW converter.

Shooting Modes

Sony A850 Modes and Menus

This page will seem very familiar if you've read our Sony A900 review, as the A850's Modes and Menus are identical.

Capture Mode: When powered on, the camera is automatically placed into Record mode. The Exposure Mode dial on top of the camera sets the main shooting mode, with the following options:

• Manual: Provides complete user control over the exposure, including both aperture and shutter speed settings. A Bulb shutter setting also becomes available in this mode, allowing variable length exposures for as long as you hold down the shutter button.
• Shutter Priority: Allows the user to set the shutter speed, from 1/8,000 to 30 seconds, while the camera selects the most appropriate aperture setting.
• Aperture Priority: The opposite of Shutter Priority, this mode puts the user in control of the aperture setting while the camera selects the best shutter speed. (The aperture range varies with the lens in use.)
• Program AE (with Shift): This mode places the camera in control over both aperture and shutter speed, while the user has access to all other menu functions. Turning either of the control dials cycles through a range of equivalent exposure settings, enabling the Program Shift mode.
• Full Auto: This mode places the camera entirely in control of the exposure, though the user can adjust the exposure compensation and determine the flash mode.
• Custom Modes 1-3: The A850 allows you to register three custom exposure modes, through the Memory option of the Record menu, so that you can quickly access your reserved settings by turning the Mode dial to one of the three numbered positions.

Playback Mode: The Playback button on the rear panel accesses Playback mode, where you can review captured images. The left and right arrow keys, as well as the up and down keys, scroll through the images on the card. You can enlarge captured images or display them in an index format for quick viewing.

Sony A850 Menus

Pressing the Menu button provides access to the camera's full menu system. The following options are available in most camera modes as menu tabs at the top of the display:

Sony A850 Record Menu:

Sony A900/A850 full Record menu layout
(note, large download for dialup users)

Sony A900/A850 full Record menu layout
(note, large download for dialup users)

Sony A900/A850 full Record menu layout
(note, large download for dialup users)

Sony A900/A850 full Record menu layout
(note, large download for dialup users)

Sony A850 Custom Menu:

Sony A900/A850 full Custom menu layout
(note, large download for dialup users)

Sony A900/A850 full Custom menu layout
(note, large download for dialup users)

Sony A900/A850 full Custom menu layout
(note, large download for dialup users)

Sony A850 Playback Menu:

Sony A900/A850 full Playback menu layout
(note, large download for dialup users)

Sony A900/A850 full Playback menu layout
(note, large download for dialup users)

Sony A850 Setup Menu:

Sony A900/A850 full Setup menu layout
(note, large download for dialup users)

Sony A900/A850 full Setup menu layout
(note, large download for dialup users)

Sony A900/A850 full Setup menu layout
(note, large download for dialup users)

Sony A900/A850 full Setup menu layout
(note, large download for dialup users)

Comparison

Sony A850 compared to other "compact" full-frame DSLRs

The chart below compares the Sony Alpha A850 with the A900, the Canon 5D Mark II and the Nikon D700. What we've done below is presented something of a hybrid comparison between these three models. A red cell means that a given camera performs below the others, a green cell means that it performs better than the others, and a yellow cell means it falls between. In cases where two cameras share a superior capability, both cells will be colored green, etc.

Press Release

Sony Brings Full-Frame Quality To A New Class Of DSLR Photo Enthusiasts

SAN DIEGO, August 27, 2009 — Aimed at experienced shooters looking for value and sophisticated SLR performance, Sony today introduced the full-frame α850 camera and a new 28-75mm F2.8 lens.

The α850 model shares the same 24.6 megapixel sensor and most features of the flagship α900 camera, introduced last year, but will be available for just under $2000 (body only).

“Sony is bringing the benefits of a full-frame digital SLR camera to a broader group of consumers,” said Kristen Elder, director of AMC business unit in the Digital Imaging Division at Sony Electronics. “The α850 strengthens Sony’s alpha DSLR line, which now offers models in each step from high-end professional down to the amateur enthusiast.”

The α850 camera is designed to deliver ultra-fine picture quality with a high resolution, 24.6-megapixel, 35-mm full-frame Exmor™ CMOS sensor and fast image processing with dual BIONZ™ processing engines. It also offers high-speed continuous shooting of 24.6 megapixel images at up to three frames per second.

Ultra-Fine Images The camera’s Exmor CMOS sensor delivers the photographic expressive power of wide angles and perspective that only a 35 mm full-frame sensor can offer, and is designed to take advantage of the resolving power of high-precision alpha lenses. Its high pixel count and large size provide enhanced image detail and a wider dynamic range for natural color reproduction and subtle tonal gradations.

Image processing gets a boost in speed and power from two BIONZ processing engines. Large amounts of data captured by the 24.6-megapixel sensor can be quickly processed to achieve a fast shooting response. Additionally, this dual BIONZ system applies advanced noise reduction algorithms producing images of exceptional quality and detail, especially at high ISO sensitivities.

Capture the Right Shot the First Time The camera’s innovative intelligent preview function takes the guesswork out of setting up a shot and the hassle of taking multiple shots to achieve a desired effect.

After pressing the depth of field preview button, the camera “grabs” a RAW preview image which is processed and displayed on the LCD screen. You can then fine tune white balance, determine the best level and effect of dynamic range optimization, adjust exposure compensation and check histogram data, all before you actually take the picture. Preview images are not recorded on the camera’s memory card, thus saving capacity.

The camera’s autofocus system features nine sensors with 10 assist points for improved tracking of moving subjects. A center dual cross sensor comprised of two horizontal and two vertical line sensors as well as a dedicated f/2.8 sensor are included to achieve greater precision, especially when using fast-aperture lenses.

Ultra-Bright Viewfinder with 98 Percent Coverage The ultra-bright viewfinder with 98 percent field of view coverage and 0.74x magnification enables accurate framing and preview. It features a high-power condenser lens, an eyepiece with high reflective-index glass, and a multi-layer, anti-reflective coating on optical surfaces to deliver its extraordinarily bright view.

A mirror box features a parallel-link mirror mechanism that moves on two horizontal axes to accommodate both the large full frame mirror and the body-integrated image stabilization system without increasing the camera’s size.

Anti-Shake System for a Full-Frame Sensor With its body-integrated SteadyShot INSIDE™ image stabilization, the camera achieves an anti-shake effect equivalent to shutter speeds faster by 2.5 to 4 stops. The anti-shake system stabilizes all Sony, Minolta and Konica-Minolta compatible lenses even wide angle or large aperture lenses.

Versatility to Unleash Creative Possibilities Other key features aimed to expand creative options include the Dynamic Range Optimizer (DRO) with five levels of user-selectable correction as well as DRO bracketing for enhanced scene analysis and graduation optimization. EV bracketing with ±2EV range makes it easy to create high dynamic range composite images.

With the camera’s HDMI™ output and Photo TV HD mode, your creative output can be enjoyed on a compatible HD television. This mode brings the look of actual printed photography to the television, by fine-tuning such image parameters as sharpness, gradation, and color reproduction.

The a850 model features a 3-inch (diagonally), Xtra Fine LCD™ screen (921K) making it possible to check focus and image quality with accuracy. It incorporates an easy-to-see display with a quick navigation menu to easily access common functions without interrupting your creative flow. A backlit LCD panel sits on top of the camera and displays key settings.

The camera includes dedicated slots for high-capacity Memory Stick PRO Duo™, Memory Stick PRO-HG Duo™, HX series and CompactFlash® media.

Bright Lens The choice of full-frame lenses to complement the α850 model is enhanced with the new SAL2875 28-75mm F2.8 SAM lens. This compact, easy-to-carry lens is ideal for photo enthusiasts looking to add a bright, general purpose zoom to their collection of full-frame optics.

Delivering excellent imaging quality at an accessible price, it offers a wide F2.8 aperture over its entire zoom range. Ideal for day-to-day shooting tasks, its bright constant aperture makes the 28-75mm F2.8 SAM particularly valuable for depth-of-field control and available-light portraits.

Pricing and Availability The a850 (model DSLR-A850) will be available in September for about $2,000 (body only) along with related accessories. All a900 accessories are compatible with the a850 camera, including the dedicated vertical grip (model VG-C90AM). The SAL2875 lens will be available in November for about $800. All will be available at authorized dealers, at military base exchanges, Sony Style retail stores (www.sonystyle.com/retail) and at sonystyle.com.

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