There are going to be those who think that Nikon is at best foolish and at worst mad to launch a new digital SLR with only 6 megapixels. After all, everyone else (including Nikon itself) has affordable 10-megapixel cameras on the market.

But that may just be a measure of how caught up we've all become in the megapixel war. After all, image quality doesn't depend solely on megapixels. Our tests of the latest 10-megapixel models suggest that they're intrinsically a little sharper than a 6-megapixel SLR, but not by an awful lot. And there does seem to be a roughly proportional increase in noise because of the smaller pixels.

All of which means we shouldn't write off 6-megapixel SLRs just yet, just because there's this temptation to get caught up in the numbers game.

The D40 isn't just a cut-down or 'refreshed' D50. It's a completely different camera with a much smaller body - the size difference isn't apparent until you actually compare the two cameras side-by-side.

The downside of the size reduction is the reduced body height. This means you can only get three fingers around the grip on the right. It's the same complaint we levelled against the Canon EOS 400D, but it's the price you pay for such compact and lightweight bodies.

The D40 loses the status panel on the top plate, too. Instead, all the shooting information is displayed on the new 2.5-inch LCD on the back. And it does look very smart indeed. You can opt for a graphical display with an impressive (but not particularly useful) circular aperture/shutter speed indicator.

The intention, presumably, is to offer a quick visual impression of the settings in use. The aperture diaphragm, for example, shrinks or enlarges according to the aperture you've set on the camera. In practice, though, you find your eyes going straight to the numerical readouts alongside, so that after a while you hardly see this graphic at all.

With that in mind, the 'classic' interface might prove more useful in the long run. This swaps to larger numerical figures and icons to indicate shots remaining, focus point, image mode and so on. Both displays look very good, and Nikon's taken a leaf out of Olympus's book by making the display interactive.

Instead of going through the menus to change ISO, white balance and so on (though you can still do this), you press a 'Setting' button on the back of the camera, then navigate to the option you want to change with the navipad. Once the option is highlighted, you press the 'OK' button to display a menu for those options.

Not so dumb

It sounds fine, but it's rather slow to use. The problem is that the info display switches off after you've taken a shot, and to display it again you have to press the Info button on the top. There are other cameras, which rely on the rear LCD for shooting information, such as the EOS 400D, but they leave it on all the time.

One other complaint. The info display is slow to react to changes. If you don't allow a moment or two to check the on-screen display has reacted fully to your input, you can easily overshoot your intended setting and take the picture with incorrect exposure settings.

Don't run away with the idea that the D40 is a dumbed down D50, mind. The image optimisation settings have been extended to include useful Vivid Plus and Black-and-White modes, and there are the same in-camera retouching options as those found on the more expensive D80.