Sony DSC-W55 Exposure

Saturation & Hue Accuracy
Slight oversaturation in red and blue tones, and somewhat warm, dark color overall.

The other important part of color rendition is hue accuracy. Hue is "what color" the color is. Like most digicams, the W55 shifts cyan colors toward blue (a very common tactic, apparently aimed at producing better-looking sky colors) and blue-greens toward cyan. Overall color accuracy was very good though, easily in the top 10% of cameras we've tested.

Exposure and White Balance

Indoors, incandescent lighting
Warm casts with both Auto and Incandescent white balance settings. More exposure compensation required than usual.

Color balance indoors under incandescent lighting was a bit warm and reddish in Auto white balance mode, while the Incandescent setting resulted in a more yellow color balance that we judged as the more pleasing of the two. (But still more highly colored than we'd prefer.) The Sony DSC-W55 required a +1.3 EV exposure compensation boost to get a good exposure, which is higher than average for this shot. Overall color is a bit dark and yellow here, making the blue flowers very dark and purplish. (A very common outcome for this shot.) Our test lighting for this shot is a mixture of 60 and 100 watt household incandescent bulb, a rather yellow light source, but a very common one in typical home settings here in the US.

Outdoors, daylight
Slightly warm color outdoors. Better than average exposure accuracy.

Outdoors, the Sony DSC-W55 showed noticeably better than average exposure accuracy, although it tended to blow-out strong highlights. Strong highlights also tended to produce slight underexposures, as in the house shot above, with a limited midtone range, but exposure accuracy was still better than average when compared to many other consumer digital cameras. Color balance was typically a little warm overall.

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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 vertically, with extinction at around 1,800. Actual resolved detail was better than with the Sony W50, but the W55's images seemed less crisp with the default sharpening setting. 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. Beware that while you might be able to make out what looks like distinct lines at numbers higher than those we've mentioned here, the camera is just doing its best to continue interpreting the lines. If you zoom in and follow them from the wider portions, you'll see the lines converge and reappear several times, so the lines you see at 1,800 and higher are really only artifacts generated by the camera's imaging system.

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

Sharpness & Detail
Fairly sharp images, with some blurring of detail from noise suppression.

The Sony DSC-W55's images tend to have a slightly soft look when printed large, though high contrast detail like the fine branches against the sky above is well-preserved, with little or no evidence of oversharpening. (Edge enhancement creates the illusion of sharpness by enhancing colors and tones right at the edge of a rapid transition in color or tone.)

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. The crop above right shows this somewhat, with darker areas of Marti's hair showing only limited detail, even though some individual strands are visible where they pass over a significantly lighter darker background. Overall though, the Sony W55 shows less loss of detail from noise reduction than average at low ISOs, but more at high ISOs.

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

The Sony DSC-W55's lower ISO settings produced low to moderate noise, with little impact on detail. (As just noted, better than average in this respect.) As the ISO setting increases though, so do the noise level and the amount of blurring that results. Shots at ISO 400 are a bit soft but still usable, while shots at ISO 800 and 1000 have so much noise and blurring that they're practically useless for printing. (Even at a print size of 4x6 inches, ISO 1000 shots are soft and muddy-looking.)

Extremes: Sunlit and low light tests
High resolution with good overall detail, though limited shadow detail and high contrast. A slight tendency towards warm casts. Fair low-light performance, capable of capturing bright images under average city street lighting.

Sunlight:
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.)

The Sony Cyber-shot DSC-W55 produced high contrast under the deliberately harsh lighting in the test above, with deep shadows and dark midtones. Detail was limited in the deep shadows as well, with some noise suppression blurring any remaining details. The W55 required less positive exposure compensation than average, however, at only +0.7 EV. You could easily argue for the "correct" exposure here to be +0.3 EV, as there are fewer blown highlights. That shot does leave Marti's skin tones rather dark, so most consumers are more likely to prefer the +0.7 EV example. (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.) Overall color was a bit warm, which darkened the blue flowers and green foliage significantly.

Low light:
The Sony DSC-W55 had somewhat limited low-light shooting capabilities, with a maximum exposure time of two seconds (only available in Twilight Scene mode) and that only at its lowest ISO setting of 100. However, the camera is sensitive enough for shooting under average city street-lighting at night, about one foot-candle. (The leftmost column of images in the table above.) Overall color was pretty good with the Auto white balance setting (just slightly pink), and the camera's autofocus system was able to focus on the subject down to the 1/4 foot-candle light level unassisted (about 1/4 as bright as typical street lighting). With the AF assist lamp enabled, the camera focused accurately down to the lowest light level we test at.

Coverage and Range
A limited flash range, even at the maximum intensity setting.

Flash coverage was somewhat uneven at wide angle, better but still slightly uneven at telephoto. In the Indoor test, the flash on the underexposed our subject at its default setting, requiring a High Intensity boost to get reasonably bright results. Even here, the exposure slightly dim. The camera's Slow-Sync flash mode produced slightly brighter and more even results, though with a stronger pinkish-orange cast from the room lighting. It too required the High Intensity flash setting for bright results.

At wide angle, shots at ISO 100 are bright out to a distance of about 10 feet, decreasing in brightness from that point on. At full telephoto and ISO 100, even the 6-foot shot is a little dim, and the images darken from there. An unimpressive flash range, at least at ISO 100.

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. In the shots above, the Sony W55 exposed properly at the officially rated distances, but only by boosting the ISO a fair bit, which increases image noise.

Print Quality
Good print quality, great color, crisp prints at 8x10 inches, acceptable ones at 11x14. ISO 400 images are a little noisy-looking at 8x10 inches, but likely acceptable for most users. Higher ISOs are usable but noisy at 5x7 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 i9900 studio printer, and on the Canon iP5000 here in the office. (See the Canon i9900 review for details on that model.)

The Sony DSC-W55 produced sharp prints at 8x10 inches, and somewhat softer but still quite acceptable ones at 11x14. As always though, the real test of print size came at the higher ISO settings. Here, the W55's ISO 400 images were a little soft and noisy when printed at 8x10 inches, but most consumers would likely find them acceptable, especially for wall display. The highest ISO settings of 800 and 1000 were quite noisy and soft, but we suspect many users would find them acceptable for use in 5x7 or smaller prints. (ISO 1000 noise is still visible in 4x6 inch prints, and colors are somewhat subdued, but most consumers would probably still find them acceptable.

Color-wise, the Sony W55 did pretty well, with bright but natural-looking color and good-looking skin tones, although we felt that many of its shots had more of a warm cast than we'd prefer.