If only size did matter ...

Published on 18/07/2003 01:00

ONE thing about technology that brings out the small boy in many of us is the opportunity it offers to compare sizes. My device has got more megahertz, megabytes, megapixels, or whatever, than yours.

Sadly, in technology as in most areas of life, size is not everything. But try telling that to your average assistant in a technology shop. Numbers, to them, are all.

To be fair, a figure is generally, by definition, an objective measure. But that does not make it meaningful. Digital cameras are a case in point. Falling prices have made them affordable even for people whose photographic activity was limited to a roll of film a year with a Christmas tree at one end and a beach at the other. So how do you decide which one to buy? If you believe most advertising, only one figure matters, the number of megapixels. But what are they?

Put simply, megapixels are the millions of dots on a light-sensitive chip which a digital camera uses instead of film. There is a parallel with printing, in that if you look at the pictures in this newspaper you will see that they are made up of dots. A glossy magazine’s pictures will look sharper, largely because they contain more and smaller dots. This is "resolution".

That does not mean, however, that the number of megapixels is all you should consider when buying a digital camera; that would be the same as saying that the quality of a non-digital camera was defined simply by the type of film it could use. In fact, it is possible to take perfectly good pictures with even a very cheap film camera.

Until recently, this was not true of digital cameras. Enlarge a digital picture and it will eventually break up or "pixelate". A one-megapixel camera cannot really produce prints bigger than 5"x7" without severe distortion. But now even some key-ring sized cameras have resolutions better than this.

Further up the scale, digital cameras have started to match their film counterparts in pricing scales. For instance, I have been playing with three Fujifilm cameras aimed at very different market sectors, but with essentially identical engines in that each has a resolution of 3.1 megapixels.

The A310 is a very easy-to-use point-and-shoot device, with 3X zoom and a limited selection of modes for close-up, portrait or landscape pictures. It costs about 280.

For an additional 50 or so, the S304 looks more like an SLR film camera. It has more exposure modes, a 6X zoom and a continuous shooting function.

Jump another 200 or so and you can buy the S602. This is a serious camera. Not only does it have a host of automatic and manual settings, the ability to take movies with sound and an excellent lens, it also has a memory slot that will take an IBM Microdrive of up to a gigabyte, meaning you can take dozens of high-quality pictures before you have to find a computer to download them. The important point is it should be possible to take pictures as good with the cheapest of these three cameras as with the most expensive. In practical terms, a 3.1-megapixel camera’s prints can generally be enlarged up to 16"x12" without distortion.

The only pity is that it is now much harder to choose a digital camera. As with buying a film camera, it really is worth reading reviews in the press and on the web (such as dpreview.com).