Will the camera be used away from school, on field trips, perhaps, or school outings? If so, it needs to be robust, have a decent carrying case, good battery management (spare batteries and a charger are also recommended) and a large storage card. It should be able to take movie clips and have zoom and macro functions.
Will it be used primarily in the classroom or around the school for general non-specific tasks that don't require high-resolution images or zoom or macro capability? If so, why not consider a dual-function webcam that can be used for web broadcasting or as a regular digital camera.
If you're going to be taking photographs for use in advanced graphics or artwork, then image resolution and lens quality become important factors, especially if you intend to print to large sizes. For taking close-up images in fine detail macro mode is essential.
Virtually all digital cameras nowadays have a built-in optical zoom lens but if you're accustomed to SLR photography you'll need to know some digital-to-35mm conversion figures. A 3x zoom approximates to 35-105mm in 35mm terms, 6x is 38-230mm 8x is 38-280 and 12x is 38-450mm.
Who will be using the camera? If it's younger students, look out for features such as non-slip rubberised grips and controls that are easy to manipulate. Generally, ensure that the camera is user friendly. For example, is the four-way controller (commonly used for menu navigation) well designed? Check that the menu system is easy to operate. The picture-taking experience can easily be spoiled by complicated software. If your students load in their own memory cards take a look at the compartment cover. Can it be opened and closed easily? More to the point, can it be broken easily! And finally, check the LCD monitor on the back of the camera. How sturdy is it? Is it large enough?
Will the camera be for the exclusive use of teachers? If so, then you could be looking at a higher-end model with the sort of manual controls and overrides that traditional camera users may be familiar with and which are capable of producing high-quality images. Even, perhaps, a model with interchangeable lenses.
What will happen to the images once they've been taken? Digital camera resolution is measured in megapixels (MPs) and, basically, the higher the megapixel number, the better the quality of the captured image. Why pay more - and you will - for a high resolution camera if you don't need that extra quality?
Five of the best
* Logitech Clicksmart 820 pound;150 Dual function web camera, 2 megapixel, full-colour LCD screen.
Canon A75 pound;150
* 3 Megapixel camera with 3x optical zoom and large LCD monitor. Supports direct printing to most Canon printers, or to any PictBridge-enabled photo printer.
Pentax Optio S4 pound;200
* 4 megapixel camera with 3 x optical zoom. Compact design.
Fujifilm S7000 (above) pound;350
* 6 megapixel camera with 6x optical zoom. Solid build, feels more like a traditional SLR.
Canon 10D pound;800
* Superb quality and good value. Great feel and handling, built to last and takes Canon lenses.