Digital camera sales are higher than ever. Not so long ago there were two well-defined camps of people who either took the digital plunge or remained faithful to film. There are still two camps, but they're divided between those shopping for their first digital or those ready to buy their second or third model.

As someone who still carries a film camera for once-in-a-lifetime shots, I'd be reluctant to describe the medium as dead, but it is being edged into an ever-specialist category, comparable in many ways to vinyl records.

As digital imaging marches towards utter domination, the question most buyers ask is how many megapixels do they really need? Resolutions are constantly on the increase and 2004 has been no different with the popular 4 and 5megapixel categories jumping to 7 and 8megapixels respectively.

In theory, these higher-resolution sensors capture finer detail, but there's more than just pixels behind decent image quality. As individual pixels are shrunk on a sensor's surface to achieve higher resolutions, they place greater demands on the optics to resolve sufficient detail.

In July I commented how steadily shrinking pixels often result in higher electronic noise levels. Having switched to a budget digital SLR with a physically larger sensor that's virtually bereft of noise, I've realised that having the most megapixels on the market isn't everything.

I reckon 5 or 6megapixels is more than sufficient for most situations. This gives you enough detail to make great-looking 10 x 8in prints. Even if you crop in on the centre and lose 50 per cent of the pixels, there'll still be enough for a good postcard print. So, while the numbers game may be irresistible, do you really need 7 or 8megapixels?

As more users become clued up about unnecessarily high resolutions, camera manufacturers are having to tempt us in other ways. Movie modes, for example, have matured from novelties into a feature worth having.

If I were buying a new camera, I'd rate 30fps VGA movie modes higher than the jump from 5 to 7megapixels. They might still seem a bit naff, but I've found that friends and family enjoy the inclusion of short bursts of video from trips more than a just series of stills.

The time limitations imposed by many movie modes work in your favour, preventing overly long clips from becoming boring and forcing the photographer to be more creative. It's certainly the feature I miss the most from digital SLRs which sadly can't offer it.

Another feature becoming increasingly fashionable is anti-shake. While traditionally only offered on high-power professional lenses, anti-shake features are used on several consumer cameras.

As their name suggests, they counteract natural camera shake, allowing us to capture sharp images even with high magnifications or using slow shutters under poor light. Admittedly they don't work miracles, but you should still be able to handhold exposures two or three times slower than normal.

Anti-shake systems are traditionally used within the lens barrel, where one or more optical elements are adjusted in real time to counteract wobbles. These systems work pretty well and it can be quite a revelation to switch them on and off on models such as Nikon's Coolpix 8800 while viewing the difference on-screen.

Possibly the most impressive anti-shake technology belongs to Konica-Minolta. Rather than adjusting optical elements, this system moves the imaging sensor itself. Motion detectors analyse wobbling and counteract it by momentarily shifting the sensor in the opposite direction, by up to 10mm in the case of the new Dynax 7D SLR.

In development at Minolta for 20 years, this technology was originally intended for 35mm film cameras. While shifting an entire frame of film proved impractical, the technology was ideal for adjusting the smaller, lighter sensors used in digital cameras.

Due to the way digital SLRs work, you won't see the effect of anti-shake through the 7D's viewfinder as you take the shot, but it's applied to any lens you attach.

Whether anti-shake is applied by adjusting lenses or sensors, it's invaluable for anyone who either shoots in low light or likes to use high magnifications. If I were shopping for a camera with a long zoom lens, it would again be higher on my list of priorities than having the maximum number of megapixels.

Camera resolutions will continue to increase and, in our conditioned greed, we'll inevitably buy them. In many cases as older models are phased out, we'll have no choice. If you want the smooth VGA movie mode and a long anti-shake lens, chances are they'll come packaged with the highest resolution sensor too.

As long as increasing resolutions don't compromise noise levels or force the use of over-zealous compression, I'm not complaining. The important thing is not to get caught up in megapixel envy and allow the marketing to convince you that today's highest resolutions should be your number one priority.

In the past it was well worth the upgrade from 2 to 3 or 3 to 5megapixels, but going to 7 or 8 is overkill for the vast majority. If the cameras have the other features you want then great, but you'll rarely if ever see the benefit of this many megapixels.

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