Digital technology has a Midas-like ability to revolutionise almost anything it touches, and media from recorded music to movie effects have been transformed with the application of mere 1s and 0s.

The world of photography is no exception and it's rare to come across an image in a magazine these days that hasn't seen a mouse click or two.

But while the digital darkroom has caught on like wildfire, the digital camera hasn't.

On the face of it, a digital camera has some big advantages over its film-using counterpart. Photographs are available for use as soon as they're taken, and they can be transferred to a PC in a matter of seconds, with no loss of quality. There's also plenty of choice, with some 70 models available in the UK from cheap and cheerful snappers to high-end models geared to professionals. So why haven't they taken off?

As ever, the main factor that's limiting digital camera uptake is price and many models cost much, much more than a similarly-specified 35mm camera.

Picture quality is also lacking and while digital camera resolutions are constantly increasing, it's still relatively easy to tell a 'real' photographic print from a digital one.

We've cast our critical eye over 15 digital cameras this month, with prices ranging from an almost spare change (for a digital camera) £99 to a wallet-bursting £859. Read on to find out what we thought.

What does a digital camera do?

Like a regular 35mm camera, a digital camera takes still photographs but rather than store them on film, they're stored electronically as an image file. The obvious advantage of this is that an image file can be read by a computer straight away, bypassing the need for developing and scanning.

This month's How IT Works (p132) explains the workings of a digital camera in more detail but suffice to say that it all boils down to a light-sensitive component called a CCD (charge coupled device) and some kind of storage device, usually a solid-state memory card.

Once you have an image that's been captured digitally, it can be manipulated in any way you choose using a computer and some image-editing software.

This can be as simple as resizing and cropping for printing, correcting the exposure, removing scary red-eye or performing some Stalinesque non-person removal. The neat thing is that because it's all done digitally, no-one will be able to tell.

Convenience is the key here. With a good-quality camera and a decent colour printer, you can be printing out perfect A4 enlargements or e-mailing your snaps around the world just minutes after you've pressed the shutter.

So why don't we all have one?

Despite the undoubted advantages, digital cameras also labour under several enormous burdens.

By far the biggest of these is cost and you can buy a very respectable SLR outfit for the same money as a merely average compact digital camera.

Pound for pound, the image quality of a digital camera is also far lower than that of a film camera since the CCD of even the most expensive model can't match the resolution of a simple strip of film. Since less detail is captured, try blowing up a digitally-acquired image to a size greater than about 6x4in and you'll soon start noticing a degradation in image quality.

Digital camera manufacturers have also tended to shy away from investment in quality lenses and this does little to help image quality either. This situation is changing though. Nikon's digital cameras use Nikkor lenses like those used for its SLR range and other manufacturers are being forced to make changes thanks to high-quality CCDs that aren't so tolerant of poor optics.

Convenience? Rapid access to photographs is all very well but unless you have equally easy access to a PC, they'll be staying in the camera until you get home. It's possible to carry a handful of memory cards around of course, but these are rather costly. This might change once Iomega launches its low-cost Clik disk and drive later this year but don't count on digital camera manufacturers moving to it overnight.

Before you buy

Digital cameras may be a gadget-lover's dream but you shouldn't rush out and buy one without doing a little thinking first.

Why do you want a digital camera?

If you've identified a serious business need that a digital camera will immediately address, then fine. Many estate agents are using digital cameras to take photographs of properties for DTP documents printed out for buyers - an application that saves both time and money.

If you want to try your hand at digital imaging at home, then think seriously about investing in a decent colour flatbed scanner instead. If you have a good 35mm camera, you will be able to digitally manipulate images on your PC for a fraction of the cost of a digital camera.

If you're sick to death of having to fire off a film before waiting a whole hour for your snaps, then a digital camera is obviously the answer to your prayers but don't be fooled into thinking that you can chuck your old camera. Using a digital camera effectively needs some discipline - the photographs you plan to keep need to be stored and indexed on a PC using some suitable software.

What to look for

Buying a digital camera is much like buying a 35mm one and a lot of the features to look out for are common to both. When looking at a digital camera, pick it up and hold it. Not all digital cameras are that comfortable to hold and unless you're happy with the way yours looks and feels, you won't be inclined to use it in public.

Viewfinder

Next, try framing a shot. If the camera has an optical viewfinder, great. If it doesn't, bear in mind that while LCD viewfinders are fine for framing shots and great for viewing them afterwards, they're useless in bright sunlight and can soon drain a set of batteries.

Lens