The Nikon CoolPix S640 is one of the top models in Nikon’s current ultra-compact line up. It is currently selling for around £190, putting it firmly into the ‘luxury’ bracket, but that price does buy a good range of features, including a 5x zoom lens equivalent to 28-140mm, a 12.2-megapixel CCD sensor and a 2.7-inch 230k LCD monitor. It features lens-shift optical image stabilisation, and Nikon claims that it performs as fast as a digital SLR.

Nikon’s advertising blurb for the S640 claims a start-up time of 0.7 seconds. I’m not sure exactly what they’re supposed to be measuring there, but the actual time from pressing the power button to taking the first picture is approximately 1.2 seconds, which is still plenty fast enough and much quicker than most of its rivals. The autofocus system is exceptionally fast, indeed almost as fast as that of a DSLR, but the shot-to-shot time of approximately 2.1 seconds, while reasonably quick by compact standards, isn’t even close to the shooting speed of even an entry-level DSLR. So much for advertising then.

The Nikon S640 also doesn’t come close to a DSLR in terms of features either. It is strictly a point-and-shoot camera, and has few manually adjustable settings. It does have a number of useful automatic features though, including lens-shift optical image stabilisation, allowing shake-free picture taking at shutter speeds as low as 1/15th of a second.

The Nikon S640 has no spot metering, no tone, contrast or sharpness adjustment, and even the colour choices are limited to standard, vivid, monochrome, sepia or cyanotype. It does have 16 scene mode programs as well as automatic scene recognition. Other shooting options include a smart portrait mode with face detection, and a subject tracking AF mode for shooting moving subjects.

For such a small camera the Nikon S640 is very pleasant to handle. The buttons are reasonably large and well spaced out, and there is a small thumb-grip area on the back. The D-pad doubles as a rotary wheel control, which usually spells trouble on a compact camera, but it is only used for menu navigation and has no function in shooting mode. The overall build quality is well up to Nikon’s usual high standard. The body is all metal, and the large bright LCD has a very wide angle of view.

Overall image quality is very good. The lens is nice and sharp, and produces virtually no wide angle distortion. Colour reproduction is excellent, with well saturated colours and a natural colour balance. Exposure and focusing are reliably accurate, and the camera performs well in low light conditions, and low light focusing is especially good, focusing in total darkness at a range of several metres.

Image noise is also very well handled. Noise is visible from 400 ISO upward, but images still have good colour, smooth gradients and plenty of detail even at 1600 ISO. The higher settings of 3200 and 6400 ISO are less good, but still far from hopeless at least for smaller images.