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White Balance

The Coolpix 2500 automatic white balance faired relatively well, gone is the 'pink' colour cast we saw under incandescent light with the Coolpix 5000, it even manages a little better under fluorescent. The pre-programmed white balances for incandescent and fluorescent seemed to be a little 'off' to me, these were better on the 5000. Manual white balance will of course produce the best results and appeared to be fairly consistent apart from the occasionally 'cool' (blue) reading.

Outdoors, Auto Outdoors, Cloudy Outdoors, Manual
Incandescent, Auto Incandescent, Incandescent Incandescent, Manual
Fluorescent, Auto Fluorescent, Fluorescent Fluorescent, Manual

Macro Focus

Previous split-bodied Nikon Coolpix digital cameras had an excellent reputation for producing very close macro shots. The Coolpix 2500 doesn't let down this tradition, switch to 'Close-up' scene mode and set the zoom between half-way and a step under telephoto and you'll get the best frame coverage. We managed to get down to an impressive 32 mm (1.3 in) across the frame.

Low Light Focus

This test measures the minimum amount of light under which the camera can still focus. The focus target is our lens distortion test chart (shown here on the right), camera is positioned exactly 2 m (6.6 ft) away.

Light levels are gradually dropped until the camera can no longer focus. This is carried out at both wide angle and telephoto zoom positions (as more light reaches the focusing systems with a larger aperture).

This test target is the optimum type of subject for most "contrast detect" AF systems (as it has a vertical line at its center), you should consider the results below the best you could expect to achieve.

Lens position Aperture Lowest light focus
Wide angle (37 mm) F2.8 3.7 EV (32.5 Lux, 3.0 foot-candle)
Telephoto (111 mm) F4.8 4.3 EV (49.2 Lux, 4.6 foot-candle)

Light intensity (Lux) = 2.5 x 2^EV (@ ISO 100), 10.76391 Lux = 1 foot-candle (fc)

When I first started using the Coolpix 2500 it became fairly apparent that it needs at least medium light levels to get a good auto focus lock. This was supported by the results of our low light AF test (above) which shows that the 2500's relatively slow lens and lack of AF assist lamp mean that it's not really designed for use in low light situations.

Flash Performance

The Coolpix 2500's flash is rated with a range of 0.4 - 3.0 m (1.3 - 9.8 ft) at wide angle and 0.4 - 1.7 m (1.3 - 5.6 ft) at full telephoto. We found that although the flash provided good colour and white balance (no colour cast) it tended to under power the flash and leave images looking darker than we'd like. Unfortunately, and as we'd expected the Coolpix 2500 does have a tendancy to produce red-eye in face shots taken in darkness. This is probably primarily attributed to the locality of the flash to the lens system.

Skin tone test: No visible colour cast, good white balance but slightly underexposed. A quick shot of our colour patches shows that the camera white balances well when using the flash but can loose some shadow detail. Wide angle 2 m wall test: As we'd expect from a small flash unit there's not quite enough power to fill out, there's even an odd dark central portion to the flash.

Barrel and Pincushion Distortion

Barrel distortion at full wide angle is quite noticeable on our test chart, we measured it as 1.5% (total distortion at the center of the frame as a percentage of the total image height). At telephoto however things are much better with no measurable pincushion distortion

Barrel Distortion, 1.5% @ wide angle Pincushion Distortion, None @ telephoto

Purple Fringing (Chromatic Aberrations)

Surprisingly the Coolpix 2500's lens did very well, hardly any visible chromatic aberrations in any of the 'every day' shots we took. Our standard chromatic aberattions test chart shot did produce some very slight purple fringing but not enough to be worried about. One thing which did become visible was a quite strong diagonal streaking effect from the bright areas of the image, I'm not sure at this stage whether this was a lens or sensor effect. We didn't see this in every day shots.

Hardly any visible chromatic aberrations in every day shots Very slight chromatic aberrations from our standard chart, quite a lot of diagonal streaking (lens effect?)

Overall Image Quality / Specific Issues

Overall the Coolpix 2500 produced acceptable two megapixel results with better than average colour reproduction. It didn't exhibit particularly high resolution or artifact free images but did manage to keep visible noise at bay and exhibitted a fairly neutral but quite well saturated colour balance. I did note that the signature 'clipped highlights' are still here giving images with sharp highlights or large contrast a slightly video-like look. In lower light the cameras automatic sensitivity pushes up to ISO 400 where some noise is visible.

Bayer Pattern Artifacts

Unlike the majority of the competition Nikon still use the CYGM colour filter array on the CCD's used in their digital cameras. The Coolpix 2500 is no exception and this goes some way to explaining the odd purple (Magenta) and yellow artifacts we saw (only occasionally) along lines of highlight in an image. Below you can see two examples of this effect which must be caused by misinterpretation of the raw data by Nikon's 'de-bayerizing' algorithms.

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