Exposure control
The size of the aperture and the brightness of the scene controls the amount of light that enters the camera during a period of time, and the shutter controls the length of time that the light hits the recording surface. Equivalent exposures can be made with a larger aperture and a faster shutter speed or a corresponding smaller aperture and with the shutter speed slowed down.

Lens
The lens of a camera captures the light from the subject and brings it to a focus on the film or detector.

Focus
only objects within a limited range of distances from the camera will be reproduced clearly. The process of adjusting this range is known as changing the camera's focus.

Image capture
The process of obtaining a digital image from a vision sensor, such as a camera.

aperture
is a hole or an opening through which light travels

shutter
is a device that allows light to pass for a determined period of time, for the purpose of exposing photographic film or a light-sensitive electronic sensor to light to capture a permanent image of a scene.

exposure
the total amount of light allowed to fall on the sensor during the taking of a photograph.

depth of field
is the portion of a scene that appears acceptably sharp in the image.

F-stop
an optical system expresses the diameter of the entrance pupil in terms of the focal length of the lens; in simpler terms, the f-number is the focal length divided by the "effective" aperture diameter.

focal length
an optical system is a measure of how strongly the system converges (focuses) or diverges (defocuses) light.