the iris
The iris diaphragm is named after the iris, the colored part of the eye, because of its similar appearance and function. Just like the iris controls the amount of light entering the eye, the iris diaphragm in a camera lens controls the amount of light entering the camera.
A camera's diaphragm and your eye's iris perform the same function in the same way. They both control how much light is allowed through the lens by expanding and contracting.
It is identical in action to the iris in your eye, it widens and narrows to allow only the required amount of light through the aperture hole/pupil
The radial and circular muscles of the iris.
The iris is like the aperture part of a camera, which used to also be called the iris.
The emulsion on the film of a camera is where the image is focused and captured. In the eye that function is performed by the retina.
Film or Paper
The pigmented diaphragm of the eye is the iris, which is the colored part of the eye. It controls the size of the pupil, which regulates the amount of light entering the eye. The pigmentation of the iris determines a person's eye color.
If you have photographic memory then your eye functions like a camera in a way
The part of the eye that is similar to the shutter in a camera is the iris. It regulates the amount of light entering the eye by adjusting the size of the pupil, functioning like a camera's aperture to control the amount of light reaching the retina.
Eye can capture an image for 1/20th of a second.And, this is how the eye works like a camera.