How Digital Cameras Work

Digital photography really works on much the same principle as traditional film phtography. When the camera's shutter is tripped, it allows light to enter the camera very briefly - sometimes for just 1/1000th of a second or less. The light strikes a light-sensitive surface inside the camera, and the "pattern" - colors, tones, etc. - is recorded on that surface.

In film photography, the light-sensitive surface inside the camera is film. Silver halide crystals in the film's emulsion react to the light, recording the image. Later, in film processing, the image is "fixed," or made permanent.

Digital photography's process is a bit more complex. In place of film, digital cameras use sensors. The image is recorded by an array of tiny receptors on the sensor, and the information from each receptor is transmitted to the camera's memory. The information from one receptor is one pixel.

Most digital cameras store the information from each exposure as a digital picture file on a solid-state "flash memory" device. (A few cameras can use a "micro drive" - a tiny mechanical hard drive.) You can then display the individual picture files on the camera's LCD screen... or download them to your computer or another digital storage device.