Aperture
a space through which light passes in an optical or photographic instrument.
the variable opening by which light enters a camera.
Shutter
a device that opens and closes to expose the film in a camera.
Exposure
the quantity of light or other radiation reaching a photographic film, as determined by shutter speed and lens aperture.
Depth of Field
the distance between the nearest and the furthest objects that give an image judged to be in focus in a camera.
F-Stop
a camera setting corresponding to a particular f-number.
Focal Length
the distance between the center of a lens or curved mirror and its focus.