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There’s one thing we can be pretty clear about. In the first edition of this title Jon was fairly sceptical about digital cameras – and with good reason at the time. But things changed pretty rapidly within the next few years. Quality went up, prices came down, and digital rapidly became mainstream. Today we feel fully justified in assuming that the vast majority of our readers use digital cameras.

Cameras

The sensor

The heart of every digital camera is the sensor, the image-forming chip which has taken the place of film. If you believe the hype, all that really matters about a sensor is how many megapixels it has. This is rubbish. Most digital cameras today have more pixels than you need, and there’s a strong argument that some have too many.

But first, what is a pixel anyway? The word is short (sort of) for ‘picture element’. In essence it’s a coloured dot. Blow up any digital photo big enough on your computer screen and you can see the individual dots of which it’s made. In a 6-megapixel camera, for example, there are (approximately) six million of these individual dots, in an (approximately) 3000 × 2000 pixel array.