cross section of a reflex camera

A slanted mirror allows the user to view and shoot at the same time; the mirror flips up when the shutter release button is pressed.

lens mount

Device used to attach a lens to a camera.

lens

Transparent optical disks through which ambient light enters; the disks correct each other to improve the quality of the image.

diaphragm

Device with a variable opening that controls the amount of light entering the camera.

light sensor

Sensor that measures the light intensity; it is used to determine the correct exposure (shutter speed and diaphragm opening).

secondary mirror

Mirror that directs part of the light entering the lens through the center of the main reflex mirror and toward the light sensor.

film

Thin flexible transparent band that is covered with a light-sensitive emulsion, which allows images to be imprinted.

focal plane shutter

Opaque device that opens for a predetermined length of time based on the shutter speed chosen; it allows light to come in contact with the film.

main reflex mirror

Mirror that redirects light toward the focusing screen; when the photo is taken, it retracts so that light reaches the film.

focusing screen

Ground glass plate on which the image caught by the lens is formed; at this point, it is inverted from right to left.

eyepiece

Optical disk or system of disks through which the eye sees the image produced by the lens.

pentaprism

Five-sided block of glass that diverts light beams to the eyepiece; this rights the inverted image formed on the focusing screen.