How a Camera works
Just like analogue file camera, your digital camera records an image using a lens to focus on
reflected light off a subject through an aperture and a shutter and then onto a focal plane. While
a film camera has a piece of film sitting on the focal plane, in a digital camera, an image sensor
is mounted on the focal plane. An image sensor is a special type of silicon chip that is light
sensitive. Currently, there are two major types of image sensors available: the charge-coupled
device (CCD) and the Complementary Metal Oxide semiconductor (CMOS).
When you take a picture, the light falling on the image sensor is sampled, converted into
electrical signals. After the image is exposed, these signals are boosted by an amplifier and sent
to an analogue-to-digital converter that turns the signals into digits. These digits are then sent
to an onboard computer for processing. Once the computer has calculated the final image, the
new image data is stored on a memory card.
<Excerpt from "Nikon Guidebook". Download the completed book here