Sony A850 Image Quality
Sony A850 Image Quality
Saturation & Hue Accuracy
Accurate color and saturation, with only minor shifts in hue and intensity.
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
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|
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.
| See full set of test images
See thumbnails of all test and gallery images
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.
|Auto White Balance
|Incandescent White Balance
|Manual White Balance
|2,600 Kelvin White Balance
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.
Very good results under harsh lighting, with good handling of contrast, detail, and color.
|Auto White Balance,
|Auto White Balance,
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.
Extremely high resolution, about 2,150 lines of strong detail.
|Strong detail to
2,150 lines horizontal
|Strong detail to
2,150 lines vertical
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.
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.
|ISO 100||ISO 200||ISO 400|
|ISO 800||ISO 1,600||ISO 3,200|
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.
|+0.7 EV||+1.0 EV||+1.3 EV|
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.)
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,
|Contrast set to lowest,
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|
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 Off||DRO Standard||DRO+ Advanced
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.
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.
Great print quality, good color, sharp 20x30-inch prints from RAW files, usable ones from in-camera JPEGs.
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.)
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