The part of the eye whose function is similar to that of the aperture stop of camera.retina,iris,lens,cornea...

I need more help from you.

The aperture is the opening between the lens and the shutter that controls the amount of light on the film. Aperatures are the same as F-stops and go f22 to f2.8. The smaller the number the larger the opening or the more light that passes through the lens when you mash the shutter to open the lens.

The aperature also controls the depth of field in a photo... which simply means that either the object closer to the camera is in focus and the back ground is out of focus or vise versa.

So... all that being said...

The cornea helps the eye focus as light makes its way through. Like clear glass, the cornea gives your eye a clear window to view the world through.

Behind the cornea are the iris, the pupil, and the anterior chamber. The iris is the colorful part of the eye. The iris has muscles attached to it that change its shape. This allows the iris to control how much light goes through the pupil.
The pupil is the black circle in the center of the iris, which is really an opening in the iris, and it lets light enter the eye. To see how this works, use a small flashlight to see how your eyes or a friend's eyes respond to changes in brightness. The pupils will get smaller when the light shines near them and they'll open wider when the light is gone.

After light enters the pupil, it hits the lens. The lens sits behind the iris and is clear and colorless. The lens' job is to focus light rays on the back of the eyeball 鈥?a part called the retina. The lens works much like the lens of a movie projector at the movies.

Your retina is in the very back of the eye. It holds millions of cells that are sensitive to light. The retina takes the light the eye receives and changes it into nerve signals so the brain can understand what the eye is seeing.

lens...a lens is a lens is a lens...get it..

What are you wanting to know? the part of the eye that opens/closes allowing more or less light in? That's the pupil.

To be more specific, the iris is the part of the eye that most resembles the aperture of a lens and works in very much the same way. The iris is a circular muscle that controls the amount of light that enters and strikes the retina, the part of the eye that captures the 'image' and processes it. The aperture of a camera lens consists of 8 to 10 metal blades creating a circular aperture that does the same for the sensor, or film frame of the camera. It's amazing how even the most advanced SLR camera's mimic something seemingly simple yet as important as the human eye to achieve only a two dimensional view of what we see in all three dimensions.