diaphragm (optics)

This article is a translation from the Dutch article on In optics, a diaphragm is a (usually round or polygon) opening in the lightpath of a lens or objective that can regulate the amount of light that passes. The centre of the diaphragm coincides with the optical axis of the lens system. Many photocameras have an adjustable diaphragm to control the amount of light, which can alternatively be regulated by adjusting the shutter time. The principle is identical to that of the iris in the human eye. A small diaphragm reduces the amount of light, but also reduces the influence of aberrations of the optical lens system and increases the depth of field. The reduced light intensity will however require the shutter time to be increased, which leads to an increased risk of movements during the time of exposure.

Diaphragm (Optics)

See also