Nikon S51c Exposure

Saturation & Hue Accuracy
Generally good color, with good overall saturation, and only slight color shifts.

Saturation. The Nikon Coolpix S51c produced good overall saturation, though yellows and some cyans are actually a bit undersaturated, while some red tones are oversaturated. Still, results are 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. Here, the S51c did render skin tones a bit on the reddish side in some cases, but results are within acceptable limits. 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 Coolpix S51c produced generally accurate color under most of our test lighting, though it pushed some yellows closer to green. The camera also produced slightly warm color balances, but overall results were pleasing. Hue is "what color" the color is.

Exposure and White Balance

Indoors, incandescent lighting
Most accurate color with the Manual white balance setting, though a hint magenta with pinkish skin tones. Less than average positive exposure compensation required.

Both the Coolpix S51c's Auto and Incandescent white balance settings produced warm color balances indoors under incandescent lighting, though the Manual option produced more accurate results. Auto white balance is really poor for this class of camera. The Nikon Coolpix S51c required slightly less than average amount of positive exposure compensation here, at +0.7 EV. Though overall color with the Manual white balance setting is a hint magenta, with pinkish skin tones, it's still pretty good overall. The blue flowers in the bouquet do have a strong purplish tint, which is a common problem among digital cameras in this shot. 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 overall color and exposure, though slightly warm color balance.

Outdoors, the Nikon Coolpix S51c tended toward a slightly warm color balance, though overall color was good. The S51c performed above average in terms of exposure, requiring less than the typical amount of positive compensation we're accustomed to seeing among consumer digital cameras for the portrait shot. The outdoor house shot was slightly overexposed at the default exposure. Contrast is a little high, though midtone detail is still pretty good. Overall a pretty good performance.

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

Resolution
High resolution, 1,400 ~ 1,500 lines of strong detail.

Our laboratory resolution chart revealed sharp, distinct line patterns down to about 1,500 lines per picture height horizontally, and to about 1,400 lines vertically. Extinction of the pattern didn't occur until past 2,000 lines. 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
Reasonably sharp images overall. Modest edge enhancement on high-contrast subjects, and a moderate amount of noise suppression.

Sharpness. The Nikon Coolpix S51c captures somewhat soft images due to noise suppression, and edge enhancement artifacts are visible on high-contrast subjects such as the crop above left. 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 a moderate amount of noise suppression in the darker areas, though there's still a lot of fine detail visible elsewhere. 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
Moderately low noise at the normal sensitivity setting, though big jumps in noise with strong blurring at the higher settings.

Noise level is moderately low at the Nikon Coolpix S51c's lowest sensitivity setting, though noise jumps with each increase in sensitivity. Significant smearing of fine detail can already be seen in darker areas at ISOs 100 and 200. At ISO 400, noise is high blurring fine detail, and purple and yellow blotches appear. The effect is even stronger at the 800 and 1,600 settings. At 800 and 1,600 ISO, noise pixels and artifacts are so bright and large that overall color balance is affected as well.

Extremes: Sunlit and low light tests
High resolution with strong overall detail, but high contrast limits shadow and highlight detail. Limited low-light performance, just capable of capturing bright images under average city street lighting.

Sunlight. The Nikon Coolpix S51c produced high contrast with deep shadows under the harsh lighting of the test above. Detail is limited in the darker shadow areas, and noise suppression is evident here as well. Marti's face appears slightly dim at the default exposure, and the image at +0.7 EV was just too hot in the highlights and on Marti's face.

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.) 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. The Nikon Coolpix S51c struggled a bit here, capturing bright images down to the 1/4 foot-candle light level (about 1/4 as bright as average city street lighting at night) only at the highest ISO setting. At ISO 100, images were dim even at one foot-candle. ISO 400 was required to capture a bright image at 1 foot-candle. The Auto white balance setting resulted in a purple cast. The camera's autofocus system was able to focus on the subject down to just below the 1/4 foot-candle light level without an AF assist lamp, matching its exposure capabilities at the higher sensitivity settings.

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.) The longer shutter times necessary here absolutely demand the use of a tripod or other camera support to get sharp photos (anything slower than 1/15 second is very difficult to hand-hold without blurring). A useful trick is to just prop the camera on a convenient surface, and use its self-timer to release the shutter. For most low-light situations, 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
Dim exposures at the default exposure setting; the camera required average exposure compensation for flash exposures. Slightly limited range.

Coverage. Flash coverage was quite uneven at wide angle, with strong falloff in the corners and edges of the frame, and splotchy coverage at the center. At telephoto, some falloff is noticeable in the corners, but coverage is a little more even. Indoors, under incandescent background lighting, the Coolpix S51c's flash underexposed our subject a fair bit at its default setting, requiring a +1.0 EV exposure compensation adjustment to get bright results. The camera's Slow-Sync flash mode didn't require any compensation, though the longer shutter speed results in a strong orange cast from the background lighting.

ISO 100 Range. At ISO 100, flash power was slightly dim at six feet at wide angle, and even dimmer at telephoto. Nikon apparently has decided to rely on its high ISO capability to capture flash shots, as suggested by the results below at ISOs 800 and 500. Those light orbs you see in some of the shots are dust particles reflecting light from the flash, and are not uncommon.

Manufacturer Specified Flash Test. In the shots above, the Coolpix S51c performs to Nikon's specifications, producing bright exposures at the rated distances with its ISO set to Auto. These seem like pretty good figures, until you consider that the camera boosts the ISO quite a bit, 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, oversaturated color, good 11x14 inch prints. ISO 400 images are soft but usable at 8x10, ISO 800 and 1,600 shots are usable at 5x7 and 4x6, respectively.

The Nikon Coolpix S51c delivered enough quality at ISO 100 for good looking 11x14 inch prints. At 13x19, its prints were softer looking, and really not good enough for display at that size. ISO 200 shots were a little softer at 11x14, but still usable. ISO 400 shots are usable at 8x10, but really better kept to 5x7. ISO 800 shots are good at 5x7, and ISO 1,600 shots are soft but decent at 4x6.

Color across the ISO range is way oversaturated, even more than it appears on the monitor. Most folks will like it just fine, though those who prefer accurate color will be disappointed. Color does decay and dim as you move toward higher ISOs, but not as badly as we've seen in the past.

Incandescent lighting produces blotches that are noticeable in the printed results down to 4x6 inches.

Note: 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.)