Sony DSC-W170 Exposure

Saturation & Hue Accuracy
Vibrant colors with slight oversaturation in red and blue tones.

Saturation. The Sony W170 oversaturates bright red and blue tones somewhat, but undersaturates some yellow and green tones just a bit. 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 W170 produced slightly pinkish skin tones, but overall results were still fairly natural. 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 Sony W170 showed fairly small color shifts relative to the correct mathematical translation of colors in its subjects, pushing cyan toward blue, red toward orange and some oranges toward yellow. Overall color accuracy was quite good though. Hue is "what color" the color is.

Exposure and White Balance

Indoors, incandescent lighting
Warm casts with both Auto and Incandescent white balance settings. Slightly less than average positive exposure compensation required.

Color balance indoors under incandescent lighting was quite warm and a bit 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.) Unfortunately, like most Sony compacts of late, the W170 does not have a custom or manual white balance mode, which would result in a more neutral color balance indoors. The W170 required a +0.7 EV exposure compensation boost to get a good exposure, a little less than average for this shot. Overall color is a bit dark and yellow here, making the blue flowers very dark, and a bit purplish. 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
High contrast, but still very good overall exposure under bright conditions. Good color as well.

Outdoors, the Sony W170 performed fairly well, despite slightly high contrast. The camera holds onto a fair amount of detail in the bright highlights, though shadow detail falls apart a little due to high noise, as well as some blurring from noise suppression. Exposure was very good, as no exposure compensation was required for either shot. Though color is slightly warm, results are quite good here, even with the higher contrast.

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Resolution
Very high resolution, 1,600 ~ 1,700 lines of strong detail.

Our laboratory resolution chart revealed sharp, distinct line patterns down to about 1,700 lines per picture height in the horizontal direction, and about 1,600 lines in the vertical direction. Extinction of the pattern didn't occur below 2,000 lines, the limit of this chart. 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 images overall, with some visible edge-enhancement on high-contrast subjects. Noise suppression limits fine detail.

Sharpness. The Sony Cyber-shot DSC-W170 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. Bright individual strands are evident, but definition is fuzzy. 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
Moderate noise at the normal sensitivity settings; stronger noise and blurring at higher ISO settings.

The Sony W170 produced moderately low noise at its 80 and 100 ISO settings, though some noise reduction artifacts are already visible at these low sensitivity levels. There's a noticeable jump in noise at ISO 200, where individual hairs are smudged together by aggressive noise reduction that's stomping out most of the fine detail. ISO 400 continues this trend, with even less fine detail and more visible NR artifacts, as well as visible chroma noise. At ISO 800, results are quite mottled, giving the image a stippled effect. Overall color balance starts to shift with purple and yellow color blotches as well. At ISOs 1,600 and especially 3,200, heavy noise reduction obliterates all fine detail, resulting in images that look more like watercolor paintings than photographs. As always, see the Output Quality section below to see how these results translate to prints.

Extremes: Sunlit and low light tests
High resolution with strong detail, but slightly high contrast and limited shadow detail. Limited low-light performance at the normal sensitivity settings, capable of capturing bright but noisy images in near darkness at the highest ISO settings.

Sunlight. The Sony W170 produced fairly high contrast under the deliberately harsh lighting in the test above, with deep shadows and bright highlights. Still, overall exposure is pretty good, with reasonable midtone detail. Shadow detail is limited, both from noise suppression efforts and noise pixels. Though there is more highlight detail preserved at -0.3 EV, Marti's face was a bit too dim to our liking, so we preferred the default exposure even though some of the highlights in the shirt and flowers were clipped. In real life, be sure to use fill flash in situations like the one shown above; it's better to shoot in the shade when possible.

Sony's Dynamic Range Optimization (DRO)
The W170 doesn't have contrast adjustment, but it does offer two settings for Sony's Dynamic Range Optimization. See the images above (all at default auto exposure) to see how it reduces lost highlights and shadows in high contrast situations. DRO Standard adjusts the curve to preserve shadow and highlight detail, and DRO plus further analyzes the image to apply more processing where it's needed.

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 W170 struggled with our low light test, limited by the 1 second maximum exposure duration (2 seconds in Night Scene mode). It was only able to capture bright images at the lowest light level when using its maximum ISO of 3,200, where noise levels are unacceptable. At the normal sensitivity settings, images were just a little dim even at the one foot-candle light level, which is equivalent to average city street-lighting at night. Color balance was pretty good with the Auto white balance setting at brighter levels, but images acquired a green cast as ISO increased and light levels dropped. The camera's autofocus system was able to focus on the subject down to the 1/4 foot-candle light level unassisted, and down to the darkest light level with the AF assist enabled. (A useful trick under these conditions 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.) 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 uneven at wide angle (no surprise though, given the 28mm wide-angle lens). Coverage was more even at telephoto, but too dark. Indoors, under incandescent background lighting, the Sony DSC-W170'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 a bit better, though with a more yellow cast.

ISO 100 Range. At wide angle, flash shots at ISO 100 remained fairly bright out to a distance of about 8 feet, decreasing in brightness from that point on. At full telephoto and ISO 100, the target at 6 feet was quite dim, getting darker from there.

Manufacturer Specified Flash Test. In the shots above, the W170 performs about as Sony says it will, producing good exposures at the rated distances with its ISO set to Auto. Unfortunately, the camera had to raise ISO sensitivity by quite a bit to achieve the bright images, resulting in excessive noise. 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, good color, sharp 13x19-inch prints at ISO 80 and 100. ISO 400 images are soft but usable at 11x14, ISO 800 shots are better at 5x7.

The Sony W170 had enough resolution to make good 13x19-inch prints at ISO 80, though with chroma noise in the shadows. 11x14-inch prints were a little better. Detail in colors starts to soften at ISO 200 when printed at 11x14, thanks to noise suppression. High contrast areas remain sharp, but not areas of subtle change, which is the theme throughout the rest of the ISO settings. There are too many color blotches at ISO 400 for 11x14 to stand, but 8x10 is better. ISO 800 shots look good at 8x10, with some minor noise that mimics film rather well; it looks better at 5x7. ISO 1,600 at 5x7 looks good in high contrast areas, but low contrast areas are just big empty fields of color. You notice this a little less at 4x6, but the lack of detail in colors is disappointing. ISO 3,200 is usable at 4x6, but I can't say that most people will like it. It's usable, but soft.

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 iP5200 here in the office. (See the Canon i9900 review for details on that model.)