a device for recording visual images in the form of photographs, film, or video signals.
Lens
a piece of glass or other transparent material with curved sides for concentrating or dispersing light rays, used singly (as in a magnifying glass) or with other lenses (as in a telescope).
Aperture
A devise that controls the amount of light admitted through an opening.
Exposure
A photograph's exposure determines how light or dark an image will appear when it's been captured by your camera.
Shutter
Focus
the distinctive bit of a photograph that is the clearest.