An image sensor is typically a monochrome device, and it needs a colour filter to produce a colour image. Each primary colour – red, green and blue – is capable of being recorded by an individual pixel, and the colour filter then filters out all but
the chosen colours for that pixel. The camera then combines the coloured pixel with its neighbouring pixels to produce the final image.
Sensors come in a variety of sizes. The majority of digital cameras contain a sensor that is smaller than a 35mm frame of film. With self-contained compacts this is not a major issue, since the lens will be designed to work with this, and will offer
either standard lens coverage or a wide to medium telephoto zoom range, in exactly the same way as a film compact would.