iris diaphragm
noun Optics, Photography.
a composite diaphragm with a central aperture readily adjustable for size, used to regulate the amount of light admitted to a lens or optical system.
Also called
iris.
Origin of iris diaphragm
First recorded in 1885–90
Words nearby iris diaphragm
iridotomy,
iridous,
iridum,
irina,
iris,
iris diaphragm,
iris family,
iris pit,
iris shutter,
iris-in,
iris-nevus syndrome
British Dictionary definitions for iris diaphragm
iris diaphragm
noun
an adjustable diaphragm that regulates the amount of light entering an optical instrument, esp a camera. It usually consists of a number of thin metal leaves arranged so that they open out into an approximately circular aperture
Sometimes shortened to: iris