Sony DSC-T20 Exposure

Saturation & Hue Accuracy
Good overall color and hue accuracy with slight oversaturation in bright reds and blues.

Saturation. The Sony Cyber-shot DSC-T20 oversaturates the strong red tones, and some blues and purples a little, but the results are still quite pleasing. 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. The DSC-T20 does render skin tones slightly on the warm side in most cases, but many consumers find slightly warm skin tones more pleasing than cooler ones. 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. Here, the DSC-T20 again performs well, though it pushes cyan and magenta tones toward blue and some reds toward orange. Still, very good results. The other important part of color rendition is hue accuracy. Hue is "what color" the color is.

Exposure and White Balance

Indoors, incandescent lighting

Warm, pinkish cast with the Auto white balance setting. Incandescent is better, but still quite warm. Slightly above average positive exposure compensation required.

Color balance indoors under incandescent lighting is quite warm, with shades of pink and yellow in Auto white balance mode, while the Incandescent setting, though still somewhat yellow, looks more pleasing overall. There is no Manual white balance setting on the T20, so the Incandescent setting is the best you'll do indoors without post-processing. The DSC-T20 requires +1.0 EV exposure compensation boost to get a good exposure, a little higher than average for this shot. Overall color is a bit pink in Auto mode, making the blue flowers look purplish. (Many digital cameras reproduce these flowers with a dark, purplish tint, so the DSC-T20's performance wasn't unusual.) 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
Good color and exposure, though slightly high contrast.

Outdoors, the Sony Cyber-shot DSC-T20 performs pretty well, with only slight overexposure in the outdoor wide shot. The Sony T20 requires the average amount of positive exposure compensation on the portrait. Contrast is on the high side, and unfortunately, there's no contrast adjustment to help compensate. The DSC-T20 captures good color outdoors, without too strong of a warm cast. Overall, pretty good results here.

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Resolution
High resolution, 1,400 ~ 1,450 lines of strong detail.

Our laboratory resolution chart revealed sharp, distinct line patterns down to about 1,450 lines per picture height horizontally, and about 1,400 lines vertically. Extinction of the pattern didn't really occur within the 2,000 line limit of this chart in either 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
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Sharpness & Detail
Sharp images overall, though slight edge-enhancement on high-contrast subjects. Moderate noise suppression limits detail in the shadows.

Sharpness. The Sony Cyber-shot DSC-T20 captures reasonably sharp images, though with slightly mottled detail. Some edge enhancement artifacts are visible on high-contrast subjects such as the crop above left, but it's minimal and not uncommon. 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 significant softening due to noise suppression, as the darker areas of Marti's hair show limited detail. 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.

ISO & Noise Performance
Low to moderate noise at the normal sensitivity settings, but very high noise and strong blurring at ISO 800 and higher settings.

Noise levels are low to moderate at the Sony T20's lower sensitivity settings, with much higher noise above ISO 400. Noise pixels are bright at the higher settings, which also throws off the color balance a bit. At ISO 800, the resulting grain pattern eliminates some of the finer details, giving the image a stippled effect. At ISOs 1,600 and especially 3,200, heavy noise reduction obliterates most fine detail, resulting in an image that looks more like a watercolor painting than a photograph.

Extremes: Sunlit and low light tests
High resolution with good overall detail, but slightly high contrast and limited shadow detail. Poor low-light performance.

Sunlight:

The Sony Cyber-shot DSC-T20 produced fairly high contrast with deep shadows under the harsh lighting of the test above. Detail is limited in the shadow areas, with some noise suppression visible. Though the shirt is nearly blown at +0.7 EV, I preferred it to the image at +0.3 EV, whose skin tones were under exposed. Depending on the photographer, you could lean one way or the other, but most T20 owners are going to want to just print an image, and the +0.7 image will produce a better print with little or no tweaking. (In "real life" though, be sure to use fill flash in situations like the one shown above; it's better to shoot in the shade when possible.)

Note: 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.)

Low light: The Sony DSC-T20 performed poorly on our low light test, mainly because its longest shutter speed is only one second. At the lower ISO settings (80 and 100), images were not bright at any level. At ISO 200, it took one foot-candle of illumination to get a borderline bright image. At 400, it took 1/2 fc, and so on. While reasonably bright, the ISO 3,200 image at 1/16 foot-candle was incredibly noisy with poor detail. The camera's autofocus system worked fairly well, able to focus on the subject almost down to the 1/8 foot-candle light level unassisted, and well past the darkest light level we test with the AF assist lamp enabled.

How bright is this? The one foot-candle light level that this test begins at roughly corresponds to the brightness of typical city street-lighting at night. Cameras performing well at that 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.) For such applications, you may have better luck with a digital SLR camera, but even there, you'll likely need to set the focus manually. For information and reviews on digital SLRs, refer to our SLR review index page.

Coverage and Range
Uneven coverage at wide angle. Poor flash range at normal ISO settings.

Coverage. Flash coverage was rather uneven at wide angle, better at telephoto (but too dark). Indoors, under incandescent background lighting, the Sony DSC-T20's flash underexposed our subject at its default setting. Using the flash's High Intensity setting helped, but results were still a bit dim. The camera's Slow-Sync flash mode fared better, though with a warmer cast.

ISO 100 Range. At ISO 100, flash power was inadequate even at six feet for both wide angle and telephoto settings. Sony apparently has decided to rely on its high ISO capability to capture flash shots, as suggested by the results below at ISO 800.

Manufacturer Specified Flash Test. In the shots above, the DSC-T20 seems to perform exactly as Sony says it will at both wide angle and telephoto, producing a good exposure at the rated distance with its ISO set to Auto. It did however have to boost ISO to 800 to do so, resulting in rather noisy images.

Note: Our standard test method for flash range uses a fixed setting of ISO 100, to provide a fair basis of comparison between cameras. We've now also begun shooting two shots using the manufacturer-specified camera settings, at the range the company claims for the camera, to assess the validity of the specific claims.

Print Quality
Good print quality, slightly oversaturated color, good 13x19 inch prints. ISO 400 images are soft but usable at 11x14, ISO 800 shots are still good at 8x10. ISO 1,600 shots are better at 4x6.

The Sony Cyber-shot DSC-T20 had enough resolution to make decent 13x19 inch prints, if a little soft on close inspection; sharpness improves at 11x14. ISO 400 images still look good at 11x14, which is quite a surprise. Contrast and saturation are increased dramatically at ISO 800, but 8x10 images are still usable. ISO 1,600 images are better at 4x6 due to dark, grainy shadows and mottled color. ISO 3,200 could have been left off the camera, as its images were really not good even at 4x6.

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 Pro 9000, and on the Canon iP5200 here in the office. (See the Canon PIXMA Pro 9000 review for details on that model.)