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White Balance

In addition to the standard auto white balance, the Coolpix 7900 has six white balance presets (daylight, incandescent, fluorescent, cloudy, shade and flash) and a manual setting. To set the white balance manually, simply choose the PRE option and a small preview appears; point the camera at a white or gray object and press enter. The manual white balance setting is remembered even if you switch the camera off. In use the auto WB did a good job when shooting in daylight, fluorescent or flash, though shooting in low incandescent light (indoors at night) produced a marked warm (orange) cast (though it is by no means the worst in its class). As with most compact cameras it is always better to use a WB preset in such situations.

Outdoor - Auto WB
Red -0.2%, Blue -0.6%
Excellent

Fluorescent - Auto WB
Red 1.8%, Blue -2.2%
Good
Incandescent - Auto WB
Red 8.4%, Blue -18.1%
Poor

Flash Performance

The 7900's built-in flash does a pretty good job in both exposure and color terms, and it offers a respectable 0.3 to 4.5M shooting range (at wideangle with auto ISO). We found the flash to be very reliable in typical shooting conditions (social occasions indoors in low light). There is a tendency to slight under exposure, though this can be fixed very easily in post-processing. We did not see any blown-out flash shots in our testing - overexposure is considerably more difficult to deal with than the slight underexposure seen here. The In-Camera Red-Eye Fix (seen on many recent Nikon models) works very well indeed - far better than cameras that rely purely on a pre-flash system; the Nikon system actually finds and corrects red-eye using its on-board processor. The only downside to this highly effective red-eye removal system is a rather severe performance hit - with shot-to-shot times stretching to around six seconds. Finally, the weak (almost inneffective) autofocus illuminator means the 7900 struggles to focus in low light (even at fairly low distances, say 3 feet), meaning the risk of out of focus flash shots is a little higher than normal.

Skin tone - no color cast,
very slight underexposure
Color chart - no color cast,
very slight underexposure

D-Lighting

Another one of the new in-camera post processing features (along with the red-eye removal) is Nikon's 'D-Lighting' feature. Press the 'OK' button when in playback mode and the 7900 will lighten shadows without affecting the highlights in the image. The effect - basically a form of in-camera contrast masking - is very similar to that used in HP's cameras, but has the advantage of being applied after the image has been taken, and the result saved as a new file. For high contrast images the results are very impressive (though inevitably they come at a small price - slightly higher shadow noise).

Original image
38 mm equiv., 1/68 sec, F4.8
After D-Lighting has been
applied in-camera.

Macro Focus

As with previous Coolpix models the 7900 has an excellent macro mode, but one that performs at its best in a small region of the zoom (near the wide end). Distortion at the closest focus point is remarkably low for such a compact camera, and edge-to-edge sharpness excellent. Close focus at the long end of the zoom is less impressive - both in terms of how close you can get and overall image quality (quite soft corners). We also found the 7900 struggled to focus in macro mode at the 114mm equiv. end of the zoom, so it's best to zoom out a little and move closer.

Wide macro - 31 x 23mm coverage
99 px/mm (2512 px/in)
Distortion: average
Corner softness: average
Equiv. focal length: 38 mm
Mid Zoom macro - 81 x 60 mm coverage
38 px/mm (962 px/in)
Distortion: low
Corner softness: above average
Equiv. focal length: 114 mm

Barrel and Pincushion Distortion

As is to be expected on a camera such as this there is some barrel distortion at the wide end of the zoom - slightly more than the average for this class of camera, though at 1.8% it is unlikely to mar real world shots. There is virtually no measurable distortion at the telephoto end of the zoom.

Barrel distortion - 1.8% at Wide angle
Equiv. focal length: 38 mm
Pincushion distortion - 0.1% at Telephoto
Equiv. focal length: 114 mm

Noise Comparison

Here for visual comparison are four identical shots taken at 50, 100, 200 and 400 ISO settings in our studio. ISO 50 is pretty clean (though the lower level of noise reduction used means it's a little noisier than some of the 7900's main competitors), and ISO 100 and 200 are perfectly usable. ISO 400 has plenty of visible noise, but it's a lot better than, say, the Canon SD500 (and the lower noise reduction means much less detail is lost), and is perfectly printable.

ISO 50 100% crop ISO 100 100% crop
ISO 200 100% crop ISO 400 100% crop

Specific Image Quality Issues

When I tested one of this camera's immediate predecessors (the Coolpix 5200) I commented on the fact that the 'out of camera' results were perhaps not particularly well tailored to the typical target user, who typically want bright, vivid, sharp results without the need to resort to post-processing. The 7900 also produces images that are far less 'processed' than the majority of its competitors, but they are much, much better than the results we got from the Coolpix 5200. Colors are natural and bright without being exaggerated, resolution is very good and exposure almost 100% accurate (with blown highlights thankfully rare). In good light the focus system is very reliable, though in low light it is much more hit and miss (see below). There is also none of the edge or corner softness that plagues the Canon SD500, nor the over-zealous noise reduction that leaves the Sony P200's results looking a little over-polished. We also saw very little color fringing at all.

Aside from focus errors in low light, the only real concern with the Coolpix 7900's output - especially using the default settings - is that they are a little on the soft side. The resolution - as our tests show - is about average for this class of camera (though the Canon SD500 beats it convincingly in the center of the frame), but the results all look soft when viewed on-screen. Increasing the sharpening in-camera to its maximum setting helps a little, but basically you need to use some unsharp masking if you want to print the Coolpix 7900's images at anything over about 6x4 inches.

Focus problems in low light

Despite boasting an autofocus illuminator (something missing from the previous generation of compact Coolpix cameras), the 7900 simply cannot focus reliably in low light at any distance or focal length setting. I found myself half pressing the button over and over again when trying to photograph a dining companion sat opposite me in a typically dimly-lit restaurant. The AF illuminator is not very bright, and certainly doesn't seem to help matters at all in these situations. The worst thing is that even when the camera finally does indicate it has found focus - on the face of your subject - the resulting photograph is often out of focus. I would estimate that when the light gets to a certain level (such as in a pub or bar in the evening) you are lucky if one out of every 10 shots you take are in focus. Switching to macro mode (which sometimes helps in these situations) failed to improve matters, though moving further away (say 2 meters) improved wideangle focus accuracy slightly. At the end of the day, however, if you want a pocket camera for social snapshots in low light then you might want to look elsewhere.

38 mm equiv., F2.8
72 mm equiv., F2.8
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