Sony DSLR-A230 Exposure

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

Saturation. The Sony A230 pushes strong reds, dark blues, and some greens just a little, but actually undersaturates bright yellows, light greens, and cyan tones slightly. Its overall color saturation is a bit higher than the A330, but still more true-to-life than that of most consumer SLRs. Most consumer digital cameras produce color that's more highly saturated (more intense) than found in the original subjects. This is simply because most people like their color a bit brighter than life.

Skin tones. Here, with the color balanced properly for the light source, the Alpha A230's skin tones looked just about right. There were some slight red tints in places, but skin tones looked pretty natural overall. 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 230 showed relatively small color shifts when compared to the correct mathematical translation of colors in its subjects. Most noticeable were a shifts in orange toward yellow-orange, yellow-orange toward yellow, and yellow toward green, with some slight shifts in cyans and blues as well. In our test subjects, we did notice that it was a little hard to distinguish between some shades of orange and yellow. Still, color accuracy was pretty good overall. Hue is "what color" the color is.

Saturation Adjustment
The Sony A230 has a total of seven saturation settings available, three above and three below the default saturation. This covers a pretty wide range of saturation levels, about as wide a range as you're likely to find photographically relevant, apart from special effects that are arguably better achieved in software. The fine steps between settings mean you can program the camera to just the level of saturation you prefer.

The table above shows results with several saturation settings, see the Thumbnails index page for more (look for the files named A230OUTBSATx.JPG). Click on any thumbnail above to see the full-sized image.

Exposure and White Balance

Indoors, incandescent lighting
Good color with Incandescent and Manual white balance settings, though warm results with Auto white balance. About average positive exposure compensation required.

Indoors, under normal incandescent lighting, the Sony Alpha 230 produced overly warm color with its Auto white balance setting. Both the Incandescent and Manual settings produced more accurate results. It was a bit of a toss-up between them, as the Manual setting was a hint cool and the Incandescent option a little warmer; We suspect most users would prefer the slight warmth of the results with the Incandescent white balance setting, as being more evocative of the original lighting. At +0.3 EV, the exposure compensation required was average for this shot. 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 230 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 230 performed well, but required slightly higher than average exposure compensation of +1.0 EV for our "sunlit" portrait shot to keep the model's face bright. (The average among the cameras we've tested is +0.7 EV.) Contrast is a little high, as you might expect under such harsh lighting, but the camera actually did a very good job of holding onto detail in both the deep shadows and bright highlights. Despite the very high apparent brightness, there are actually very few clipped highlights in the model's face and shirt, with most of the clipping occurring in the pendant and flowers. The highlights were also blown out just a bit in the House shot, but not too badly. 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 did change slightly - See the Contrast series under the Extremes section below). Overall, very good performance.

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

Resolution
High resolution, 1,500 ~ 1,600 lines of strong detail.

Our laboratory resolution chart revealed sharp, distinct line patterns down to about 1,600 lines per picture height in the horizontal direction, and about 1,500 in the vertical direction. Extinction didn't occur until around 2,600 lines. Unusually, we weren't able to do much better with Adobe Camera RAW processed RAW files. 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
Slightly soft results overall with the kit lens, but sharp, detailed images with an excellent lens. Only minor edge-enhancement on high-contrast subjects. Minimal noise suppression visible.

Sharpness. The Sony A230 produced good detail, but softness in its kit lens didn't show off the camera's abilities to best advantage. The crop of the house and trees above is from an image shot with Sony's 24-70mm f/2.8 Carl Zeiss zoom, a really excellent optic, and shows the good detail the A230 body is capable of. Some edge enhancement artifacts are visible on high-contrast subjects such as the crop above left, but overall results are still good. 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 minimal noise suppression, 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, and some areas of particularly subtle contrast still blur somewhat. Still, good performance here. Noise-suppression systems in digital cameras tend to flatten-out detail in areas of subtle contrast. The effects can often be seen in shots of human hair, where the individual strands are lost and an almost "watercolor" look appears.

RAW vs In-Camera JPEGs
As noted above, the Sony A230 produces fairly sharp, detailed images with minor visible sharpening artifacts in camera JPEGs. Still, a little more detail can be obtained from carefully processing RAW files though, without additional artifacts. Take a look below, to see what we mean:

In the table above, mousing over a link at the bottom will load the corresponding crop in the area above, and clicking the link will load the full resolution image. Examples include in-camera Fine JPEG, RAW file processed through Sony's Image Data Converter SR version 2 software, and RAW file processed through Adobe Camera Raw version 5.5, then sharpened in Photoshop. For the Sony A230's images, I found best results with strong but tight 300% unsharp masking with an 0.3 pixel radius.

Note: ACR renders colors somewhat differently than either the A230 or the Sony software, so the greens in the trees are rather different. There's no mistaking the increase in detail though, regardless of changes in color or tone.

ISO & Noise Performance
Low noise at the normal sensitivity settings, with very good results up to ISO 400. Noise jumps significantly at ISO 800 and above, though.

The Sony Alpha 230 produced low noise at its lower sensitivity settings, and even at ISO 400, noise is well controlled, with plenty of detail left intact. At ISO 800, the noise level increased significantly, and fine detail began to suffer, with some chroma noise visible in darker tones. At the higher settings of 1,600 and 3,200, noise levels were much higher, with heavy blurring and chroma noise blotches. The ISO 3,200 shot is also a bit darker than the others, indicating a slightly non-linear sensitivity response at the highest ISO. See the Print Quality section below for recommended maximum print sizes at each ISO.

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

Extremes: Sunlit and low light tests
High resolution and good exposure at the default setting. Very good shadow detail. Good low-light performance, capable of capturing bright images in near darkness, but autofocus and metering struggled at lower light levels.

Sunlight:
The Sony Alpha 230 handled the deliberately harsh lighting in the test above pretty well. Though contrast is a little high, shadow and highlight detail are very good. The camera's contrast adjustment also did a good job of decreasing overall contrast without producing strong color variations. The +0.7 EV exposure did the best job here, as the model's face was a bit too dim at +0.3 EV and +1.0 EV produced very strong highlights. (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 A230's contrast setting meets both challenges.

At its lowest contrast setting, the A230 did an excellent job of preserving highlight detail, maintaining natural-looking skin tones, and holding nice detail in the shadows. The A230 captured good color outdoors, though just a little on the warm side. Overall, very good results here, especially when the contrast setting was tweaked. (A very tough shot; the Sony A230 does much better than average here.)

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 effect of the extreme settings here, 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, so it's a good trick to be able to vary one with out the other changing as well. There are a few minor color shifts in the images above, but they're pretty minor indeed, so we'd have no qualms about using the contrast adjustment control whenever we're faced with harsh lighting. Sony did a good job here.

Sony's DRO (Dynamic Range Optimization)
While the Sony A230's contrast adjustment feature works very well, their Dynamic Range Optimization system is designed to take it to another level. This system analyzes the range of brightness of each image, and adjusts the camera's image processing parameters accordingly, to make the best use of the available dynamic range. Three options are available on the A230: DRO Off, Standard D-R, and D-R Advanced (Plus). In Auto exposure mode, or in Portrait, Landscape or Macro, DRO is automatically set to Advanced. In Sports mode, DRO is set to Standard. DRO is set to Off in Sunset and Night Portrait/View mode. Unlike some of Sony's higher-spec cameras, the A230 does not allow you choose the strength for the D-R effect. Standard D-R looks at the entire image and effectively adjusts contrast and brightness across the entire image for best effect. D-R Advanced analyzes everything, but makes local adjustments to bring out shadow detail and preserve highlights.

As you can see from the crops above, to get a similarly exposed image without DRO enabled, about +0.7 to +1.0 EV positive exposure compensation is required. Other than that, the effect of DRO is quite subtle (in this case anyway). You can see more highlight detail with DRO set to Advanced versus Off, but DRO Standard seems to clip slightly more highlights than when DRO is set to Off. Shadow detail is similar in all three similarly exposed cases, but there is an increase in noise in the deepest shadows with DRO enabled. Note: the shadow crops have had levels adjusted equally (by sliding Photoshop's highlight slider to 100) on the right side of each to reveal the increase in shadow noise with DRO active.

Low light. The Sony A230 performed reasonably well on the low-light test, capturing usable images at the lowest light level with the lowest sensitivity setting (ISO 100). Manual exposure had to be used however, as the A230's exposure metering was not reliable at lower light levels. Noise is fairly low below ISO 800, and consists mainly of chroma blotches at higher ISOs. There's no sign of any banding issues or uncorrected hot pixels. Color balance looked good with the Auto white balance setting.

The camera's autofocus system struggled a bit in low-light, compared to most SLRs, as it was only able to focus on the subject down to somewhere between the 1/2 and 1/4 foot-candle light level unassisted. It was however able to autofocus 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, Sony's Super SteadyShot not withstanding. (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 A230 do much better than point & shoots, but you still shouldn't expect a quick autofocus lock with moving subjects.

Print Quality
Great print quality, good color, sharp 13 x 19-inch prints at ISO 100.

The Sony A230's printed output is pretty good, with a fairly even approach across the ISO spectrum. ISO 100 shots are very slightly soft at 13x19, but only on close inspection; otherwise they look quite good.

ISO 200 shots are soft enough at 13x19 inches that I reduced the resolution to 11x14 with much sharper results. ISO 400 shots also looked good at this size, and ISO 800 shots are quite usable, if only a touch soft.

ISO 1,600 looks good at 8x10, which was surprising, since we saw the quality fall apart at 100 percent onscreen. Which is why we do the printing. ISO 3,200 was a little rough at 8x10, though, yet quite usable at 5x7.

So overall, the Sony A230 made very good quality prints with low noise and good color.

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 Canon Pixma MP610 here in the office. (See the Canon Pixma Pro9000 Mark II review for details on that model.)