Summary

It takes several steps for a digital camera to take a picture. Here's a review of what happens in a CCD camera, from beginning to end:
  • You aim the camera at the subject and adjust the optical zoom to get closer or farther away.

  • You press lightly on the shutter release.

  • The camera automatically focuses on the subject and takes a reading of the available light.

  • The camera sets the aperture and shutter speed for optimal exposure.

  • You press the shutter release all the way.

  • The camera resets the CCD and exposes it to the light, building up an electrical charge, until the shutter closes.

  • The ADC measures the charge and creates a digital signal that represents the values of the charge at each pixel.

  • A processor interpolates the data from the different pixels to create natural color. On many cameras, it is possible to see the output on the LCD at this stage.

  • A processor may perform a preset level of compression on the data.

  • The information is stored in some form of memory device (probably a Flash memory card).


Photo courtesy HSW Shopper
A memory stick

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