Question

what is iris diaphragm

Answer 1

Answer:

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.

Explanation:

Answer 2

a flat, colored, ring-shaped membrane behind the cornea of the eye, with an adjustable circular opening (pupil) in the center.
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