Question

Aperture is controlled by what in the camera?

Answer 1

its usually controlled by an iris..

Answer 2

In the human eye, it's the iris. On a camera, aperture is controlled by the diaphragm. This determines the diameter of the lens' opening. The diaphragm limits the amount of light entering the lens. It "stops" the passage of light, which is why the aperture settings are called field stops, "f-stops" for short.

Source: photography minor in college