How Does a Camera Work?

old camera

There are amazing pictures of Newton, George Washington, Beethoven, and other famous men of earlier times. But these pictures are paintings, not photographs. Photographs became possible only a little more than one-hundred years ago after the camera was invented.

A camera is a light-tight box. Light can come into it only when a shutter is pulled away from a small opening at the front. Then the light shines in through a lens in the opening. The lens throws a picture of what is in front of it on a film or a plate at the back of the box. This film or plate is coated with a chemical sensitive to light.

Fortunately a camera lens can throw on a plate or film a small picture of a very large object. Otherwise, we could not take pictures of big buildings or clouds or crowds of people. After a picture is taken, the plate or film has to be developed.

A camera may cost only a few dollars or it may cost hundreds of dollars. One big difference between a cheap camera and an expensive one is in the quality of the lens. The best lenses are very expensive because they are very carefully ground.

Moving picture cameras are much like other cameras. They simply take one pic­ture after another very rapidly.