The Action of Light
Traditional Film Camera
The camera lens focuses the light reflected from the subject. The light passes through the aperture and hits the film. This causes a chemical reaction in the light-sensitive silver halide particles of the film, creating a latent image. Chemical processing develops this image into a negative.
The charge coupled device (CCD) converts light into a digital signal. Its surface is divided into tiny squares called pixels, short for picture elements. These are like small tiles in a mosaic. Each pixel records one small part of an image. It has an electrical charge, or signal, proportional to the amount of light falling on it. The analog-to-digital converter converts the signals from the CCD so the computer can read them.