It's official: UK plcs are buying more digital cameras than 35mm cameras from Dixons, the major high-street retailer. Last year digital outsold 35mm during the spring and this year the company believes there will be more digital sales overall.

But it's not as simple as just picking up a camera. There are digital cameras attached to other devices, digital cameras that attach to other devices, digital cameras that are part of other devices, digital cameras for under £50 and digital cameras for over £500.

It's a case of finding a camera to suit your needs. The first piece of advice to anyone thinking of buying is that if you haven't needed a digital camera for your job before then you probably don't now. If you require something really basic for ID badges and not much else then a dedicated digital camera may not be necessary.

Something like a webcam, which allows you to take still shots, will do. The advantage of using, say, the Logitech QuickCam Cordless (£179.99) is that although it's expensive it will also work as a security system, monitoring rooms you're not in. If budgets are tight and you definitely want a camera for low-resolution photography then something like the SiPix Groove - with 1.3 megapixels but extra software to brighten up the pics once they're on your computer - should do nicely at around £50 when it comes out in May.

There are various devices to which a digital camera can be attached, or which have a built-in camera. Many phones have them, or they clip them on, and you can add a camera from Veo to your Palm for £79.99 (or indeed get the new Palm Zire, which has a camera built in, for £250; if you were already considering a Palm, this is essentially a hand-held computer for consumers with a free camera on the back). If, say, you're a small estate agent who wants to attach snapshots of houses to details really quickly one of these solutions will work well.

If your needs are more sophisticated then you'll need to look more upmarket. The best advice for digital camera selection applies to all cameras: choose one from a well-regarded brand and you can't go far wrong. Malcolm Kirk, head of business sales for camera specialist Jessops, has noted an increase in digital interest and believes businesses like to view the image as soon as it has been taken and to improve it using manipulation software.

"The majority of business purchases tend to be the value-for-money, medium-range consumer models that are ideal for general use," he says. "These typically come with a zoom lens that will magnify the subject two or three times, a built-in flash for use in poor light and an LCD screen." Image resolution is typically two to three megapixels, which will look good on a 10x8 print. And Jessops has a printing service that will make a digital pic look like a 35mm image. Expect to pay £175-£300 for something like that.

One of the more popular models at Jessops is the Olympus Stylus 300, 3.2 megapixels and a good zoom. Other options include the Kodak Easyshare LS633, which has a larger, sharper LED for better picture previews, and the Pentax Optio 550, all of which offer comparable features and pricing.

Other, flashier offerings are available too if you want them. Casio's Exilim range has just been upgraded with the EX-Z3, for which you get a 3 megapixel camera with a zoom lens, all in a casing that feels smaller than a deck of cards.

And of course there are the £500+ cameras, for example the excellent Fujifilm FinePix S602 Zoom with a vastly better zoom, more robust casing and other technical wizardry. It's aimed at the serious professional who knows exactly what they want their machine to do and would be wasted on the casual user.

Frankly, if your needs are of that order you need a professional photographer who'll know how to use it and who'll already own their camera of choice.

Putting you in the picture

Ideally, digital cameras should be simple to use and light enough to handle, except at the specialist, professional end where you're into tripods and all the trimmings. However, even at the lower end there are things to watch for:

· Look out for the storage capacity and the interchangeable memory. If your camera takes, say, Sony memory sticks then you'll need a PC that also takes them - they don't all do so. If it takes standard memory cards then they'll almost certainly fit into your PDA but you might want to buy an external card reader (like the Imation FlashGo! - £60) to attach to your PC. Add-in memory cards are available from TDK and others, are fully erasable/rewriteable and can take up to 100 pictures at a time.

· For attaching to your PC, USB is fastest and almost universal - but if your computers are more than a few years old they may not have the right slot.

· Think about the paper you'll be printing on as well as your printer, if printing is your objective - skimp there and it'll be embarrassingly obvious.

· If you buy something for low-resolution pictures and spend less than £50, expect it to do the job but don't expect it to take the pics for your snazzy corporate brochure - you can't expect miracles for fifty quid.