The key difference is that instead of focusing the light on a strip of photochemical film as in traditional cameras, digital cameras use an image sensor, called a charge coupled device (CCD), to capture the image.

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Take, for instance, charge coupled devices (CCDs).

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Then in the early 1990s cameras built on charge-coupled devices, or CCDs, became available to amateur astronomers.

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Traditional cameras use either charge-coupled devices (CCDs) or complementary metal oxide semiconductor (CMOS) chips, which capture images on a grid of millions of pixels.

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Inside is a 1.18 million-pixel charge-coupled device, or CCD.

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Apart from the arrival of less pricey full-frame digital SLRs, the other recent development that has impressed your correspondent is the way imaging chips are migrating from CCD (charge-coupled device) technology to CMOS (complementary metal-oxide semiconductor), used widely in the computer industry.

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