iris diaphragm

nounOptics, Photography.
  1. 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.

Origin of iris diaphragm

First recorded in 1885–90

Words Nearby iris diaphragm Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use iris diaphragm in a sentence

British Dictionary definitions for iris diaphragm

iris diaphragm

  1. 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

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