What is a Camera?

Any camera is made up of four basic things.

 

Body - a light-tight box to hold and transport the film
Lens - to collect light and focus it on the film
Shutter - to control the amount of time that light is allowed to pass to the film
Diaphragm - to control the amount of light allowed through the lens to the film

Body

The camera body is a light-tight box that holds and transports photographic film, and includes a shutter release button used to take the picture. The camera body may be as simple as an old fashioned pinhole camera or as sophisticated as a modern single lens reflex with high tech light metering systems and built in mini-computers.

Lens

The lens collects and focuses light rays, transmitting them into the camera body and onto the film. The lens can be as simple as a pinhole or as sophisticated as a modern, multi element, auto-focus zoom lens with built in mini-computers and motors.

Shutter

The shutter controls the length of time that light is allowed to pass through the lens and onto the film. Focal plane shutters are located within the camera body, and leaf shutters are located within the lens. Most cameras have only one type of shutter, but a few professional cameras have both types of shutters.

Diaphragm

The diaphragm controls the amount of light that is allowed to pass through the lens and onto the film. The diaphragm works like the iris in the human eye, and can be opened or closed to adjust to varying degrees of illumination.