Sony DSC-W70 Exposure

Exposure and White Balance

Indoors, incandescent lighting
A warm cast with both Auto and Incandescent white balance settings, average positive exposure compensation required.

Color balance indoors under incandescent lighting was quite warm and reddish in Auto white balance mode, and the Incandescent setting also resulted in a pronounced warm cast. The Sony DSC-W70 required a +1.0 EV exposure compensation adjustment, which is about average for this shot, though the highlights on Marti's shirt are quite hot at that setting. In addition to the strong warm cast, overall color is a bit dark 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 pretty yellow light source, but a very common one in typical home settings here in the US.

Outdoors, daylight
Good overall exposure and color outdoors.

Outdoor shots generally showed nearly accurate exposure with slightly blown out highlights. Shadow areas held onto a good amount of detail, though with some noise suppression to lessen definition. Overall color looked good as well, if just a hint dark in some cases.

See full set of test images with explanations
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Resolution
High resolution, ~1,300 lines of strong detail.

Our laboratory resolution chart revealed sharp, distinct line patterns down to about 1,300 lines per picture height, with extinction at around 1,800. 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 1,700 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
Sharp images overall, though some blurring of detail from noise suppression.

The Sony DSC-W70's images are sharp and clear overall, without any strong over-sharpening or edge enhancement on the camera's part. (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 of Marti's hair above shows this in the darker shadows, though quite a few individual strands of hair are visible in the brighter shadows and highlights.

ISO & Noise Performance
Moderate noise at the normal sensitivity settings with slightly blurred detail, but very high noise with stronger blurring at the higher settings.

The Sony DSC-W70's lower ISO settings produced moderate noise, with only slightly blurred detail in the dark areas. As you'd expect, noise level increased significantly with the higher ISO settings, resulting in a stronger noise pattern and stronger blurring. That said, most consumers would probably consider ISO 400 shots usable at print sizes as large as 8x10 inches. Shots at ISO 800 and 1,000 are noisy and a little soft even at 5x7 inches, but just fine for 4x6 prints.

Extremes: Sunlit and low light tests
High resolution and strong detail overall, though slightly limited shadow detail. Pretty good low-light performance, capable of capturing bright images under average city street lighting and slightly darker conditions.

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-W70 performed fairly well in response to the deliberately harsh lighting in the test above, though contrast is slightly high and shadow detail a bit limited. Noise suppression in the shadows also contributes to the loss of detail. Although Marti's skin tones and some of the foliage of the flower bouquet is a little dark there, the best exposure was obtained at +1.0 EV, which is about average for this shot. Though midtones are brighter at +1.3 EV, highlights are just too hot. (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.)

Low light:
Our low light testing revealed some limitations in the DSC-W70's lens and sensor abilities, though the camera is capable of capturing bright images under average city street lighting at night (about one foot-candle). At the higher ISO settings, images were bright down to about 1/4 foot-candle, which is about a quarter the brightness of average city street lighting. 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 we test at with the AF assist lamp enabled. Keep in mind though, that the longer shutter times here demand the use of a tripod or other camera support to get sharp photos. (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.)

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.