The Nikon D200 was a truly great camera that offered professional performance at an enthusiast's price. Even now, its 10-megapixel CCD sensor can easily hold its own compared with similarly-priced rivals, and the robust build quality was - and still is - out of this world.

But Nikon clearly thought that it could do even better. And the result of its thinking is the brand-new D300, a camera that looks outwardly like the D200 but which includes a number of highly significant technical advances and real improvements when it comes to image processing.

The most notable of these improvement is the new 12.3-megapixel CMOS sensor which is remarkably 'similar' to the Exmor model used in the new Sony Alpha A700. Of course, adding two million extra pixels isn't going to make much difference to the image quality, but this isn't just a reheated version of the old sensor.

Nikon's swapped from CCD to CMOS technology with a brand-new and advanced sensor design that delivers more than just a few extra pixels. There's the increased ISO range, for a start. This runs from ISO 200-3200, with 'extended' settings of ISO 100 and ISO 6400 for extreme lighting conditions.

The maximum frame rate is up slightly from 5fps to 6fps, and the D300 can keep this up for around 100 JPEGs or 20 RAW files. The 51-point AF system is also new, as is the stunning 920,000-dot 3-inch LCD display, which is identical to the one on the Alpha 700.

Live View

And then there's the Live View mode (two modes, in fact), a feat once thought impossible with a digital SLR but now becoming commonplace, first on Olympus E-series cameras, then appearing on Canon SLRs and now showing up here. It's not like using a compact camera, though. With the D300, there's so much shunting of mirrors and flapping of shutters that you can easily lose track of whether the camera's taken a picture or if it's just focusing.

Live View modes also raise the spectre of dust - a perennial problem with digital SLRs anyway. But if the mirror's going to be up and the shutter open for extended periods of time while you compose the shot on the LCD, dust spots become much more likely. The D300 tackles this with a new dust-removal system which, like others, uses vibrations to shake the low-pass filter in front of the sensor.

These improvements aren't minor evolutionary changes, then. The D300 is a genuine advance over the D200 in a number of important areas.

Some things haven't changed - notably the build quality and the control layout. The D200 always seemed a heck of a lot of camera for the money, and so does the D300, though the launch price of £1,300 does seem pretty steep when compared with what the outgoing D200 was selling for (well under £900 by the end of its life).

That's a premium of £500! It's a heavy but incredibly solid-feeling camera, and all the dials, knobs and buttons feel firm and tough too. The only let-down here is the navipad, which feels much too vague and has a smooth finish that your thumb can too easily slide off.

In the hand

With around two dozen controls on the top and back of the camera, there's an awful lot going on and quite a lot to learn if you've not used this type of camera before. Here, the D300 contrasts heavily with Canon's design for its EOS range of SLRs, which seem far less fussy but manage to do all the same things. However, Nikon fans will love the D300 because everything is placed where they expect to find it - newcomers may find it a little complicated though. This is clearly one of those areas, though, where personal preference will play a big part in the buying decision.

The other point worth making is that this is a professional camera. It may not be as big as a Canon 1Ds or a Nikon D2x, but it's a serious step up, both in terms of size and weight, from an 'amateur' SLR. Compared to, say, an Olympus E-410 or a Nikon D40x, it's not that much fun to carry around all day.

And then there's the choice of lens. A camera of this calibre demands the very best quality optics that you can afford. Our review unit was supplied with a Nikon 17-55mm f/2.8, a DX lens which only really comes into its own when matched up to a top-quality camera.

But this is a £900 lens! What's the alternative? Perhaps a Nikon 18-70mm, or 18-135mm? Both these 'amateur' lenses might be acceptable for a D40x or a D80, but they hardly seem a fitting match for the D300. (Nikon's 18-200mm VR could be a good choice, though).