The iris is the adjustable opening that can restrict the amount of light that enters the camera. It's the shutters and springs that actually open and close. Aperture — The aperture is the hole in the opening of the iris.

Is the pupil like an aperture?

As previously mentioned, the pupil and iris act like the aperture of a camera, regulating the amount of light that can travel through the lens into the retina. ... Compared to a camera lens, the human pupil rests around 4 mm in diameter. In extreme dark, it dilates to approximately 8 mm (f/2.1).

What is the small aperture in iris called?

So, the circular aperture through which light enters the eye is the pupil. The pupil is a black circle in the centre of the iris.