The film because it forms the real image just like the retina.
The reflection mirror.
The iris is like the aperture part of a camera, which used to also be called the iris.
the iris
The iris acts like the aperture of a camera lens.
iris
Like fingerprints, a person's iris is unique. An iris scan is accomplished by a system that uses a device like a digital camera to record details about a person's iris. The image is converted to an iris code and stored in a database for future use.
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 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.
The iris diaphragm in a camera is most similar to the iris in the human eye. Both structures regulate the amount of light entering the system.
As in a camera, this part is usually called an iris diaphragm. It can make the aperture bigger to let in more light, or smaller to make the image sharper. The shutter in a camera is not the same thing.
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.
iris
f-stop