Conventional sensors have a limited dynamic range. This means that high-contrast scenes may have solid black shadows, blown highlights, or both, depending on the exposure compromises you and the camera make.

This happens because the individual pixels, or photosites, on the sensors can only cope with a certain brightness range. At one end of the range, they don't capture enough photons to register any kind of signal; while at they other they capture so many that they're saturated.

What you need is a sensor with different-sized photosites: larger ones for everyday photography; and some smaller, lower-sensitivity sites for hanging on to detail in highlights. Fujifilm's SR sensor is the only one to tackle this issue.

Its combination of large S-type pixels and smaller R-type pixels offers a dynamic range up to 400 per cent wider than that of conventional sensors. The FinePix S5 Pro uses this SR sensor, as did its predecessor, the S3 Pro, and the design has also been tried out in a couple of Fujifilm compacts.

How many megapixels?

The S5 Pro has 6 million 'S' pixels and 6 million 'R' pixels. In older designs they were 'paired', but now they're interleaved on the sensor surface, so it's even harder to say whether this is a 6MP or a 12MP camera. By default, the S5 Pro outputs 12MP files, and because these pixels don't share the same physical location, we've referred to it as a 12MP camera.

The proof lies in prints, not pixel values. The S5's colours are excellent and its rendition of skin tones is somehow richer and more 'open' than any other camera's. Its increased dynamic range is apparent, too; not just in the extra highlight detail it retains but in the smooth tonal transitions at these brightness extremes. However, as with the S3 Pro before it, the internal JPEG processing doesn't quite do justice to the extraordinary level of highlight detail dormant in the RAW files.

Annoyingly, you don't get RAW conversion software with the camera. Or you do, but it's only a version built into Fujifilm's basic FinePix viewer. This can convert RAW files using the settings dialled into the camera at the time of shooting, but it doesn't offer the 'reprocessing' options found in Fujifilm's HyperUtility software (a £100 optional extra).

All change?

While the 12MP SR sensor in the S5 Pro might appear to share the same spec as that in the S3 Pro, there are some big differences on the image processing and hardware fronts. The image processing has been revised heavily to offer better quality and an extra-high ISO 3200 setting.

The results we got from this camera are striking. Noise is essentially non- existent at ISO 100/200, and only slight at ISO 400/800. The S5 Pro's high-ISO performance is deeply impressive. If you're worried that the noise reduction is taking away too much low-contrast textural information, you can reduce the amount applied. You get more grain (though still not an objectionable amount) and a little more detail.

The S3 Pro offered three main picture modes: Standard, where you could adjust the dynamic range (normal and wide), contrast, sharpness, tone and saturation; F1 for simulating the smooth tonal properties and wide contrast range of a negative film; and F2 for simulating a high-contrast, high-saturation slide film.

It's hard to see the reason for having five dynamic range options in the new camera, though, ranging between 100 per cent (no extra) to 400 per cent (the maximum). Surely you're just going to want one or the other? Especially since in Standard mode the camera can adjust the dynamic range to match the scene brightness.

The image processing changes are significant, but it's on the outside that the biggest changes have taken place. This is a very different camera from the S3 Pro, and for reasons that can be explained quite simply: Fujifilm doesn't make its own SLR bodies - it uses adapted Nikon bodies instead.

The S3 Pro was based around a 'digitalised' Nikon D80 film camera, a rather dated design but one that handled well enough. The S5 Pro, though, uses the Nikon D200 body, which is chunkier, better made and much more a 'pro' camera than the plastic-panelled S3 Pro.

You get a much bigger viewfinder than that on the S3 Pro, a bigger 2.5-inch LCD and a cleaner control layout with a large status LCD on the top-plate.

The S5 Pro's menu system isn't as elegant looking as the D200's but it works well enough. The Fujifilm can't match the Nikon's continuous shooting speed, presumably because of the extra image processing required, and it's suprising to see that there's no xD card slot.

Put the two cameras side by side and you've got an interesting choice. Do you go for the cheaper Nikon with its bright, punchy, picture rendition, or the subtly superior tonal response and wonderful skin tones of the S5 Pro? The Nikon's great for stock photography, wildlife and sports, but if your interests are still life, portraiture or more considered pictorial photography, the S5 Pro is the best digital SLR you can get. Rod Lawton

Via PhotoRadar