iris diaphragm
noun
Forms iris diaphragms
- noun An adjustable diaphragm by which the diameter of an approximately circular opening may be controlled, as for regulating the aperture of a lens; it consists of a number of movable thin curved plates fastened at regular intervals around the inside of a ring, the positions of which are simultaneously adjusted by a single knob on the outside of the lens. It is used in cameras and microscopes.
Synonyms
Etymology
Derives from its action which is reminiscent of the iris of the eye.
Webster’s 1913
- An adjustable diaphragm, suggesting the iris of the eye in its action, for regulating the aperture of a lens, consisting of a number of thin pieces fastened to a ring. It is used in cameras and microscopes.
Sources: Wiktionary · WordNet 3.0 · Webster’s 1913 — from the Wiktionary entry “iris diaphragm”, CC BY-SA 4.0. Details