The lens.
The lens
the lens
opening that lets light in
The iris (technically the diaphragm) lets light from the lens enter the camera. The entire lens can let light fall on the film or sensor. But, much of the time it doesn't do that. An device called an iris makes the hole through which light passes larger and smaller. When all the way open it lets light from the entire lens reach the film or sensor, but it can make the hole smaller and only allow light from a part of the lens enter.
When you click the camera the shutter behind the lens of the camera opens briefly and lets in the light on to the film. I am no specialist and this is what I learnt in school.
The largest camera aperture is f stop 1.4, which lets the most amount of light into the camera.
The lens.
The shutter.
Modernern cameras use a shutter system. Although it is possible to make a camera with a pin hole. But either way there needs to be a mechanism to stop the light from hitting the light sensitive paper which would be a shutter.
Ocular lens
This part is called a Lens, on the camera and the glasses the are made of either optical glass or optical plastic, in the eye the lens in an organic material. Lens allow light to enter the camera, eye or glasses, and focuses that light on a surface such as the camera's film, the eye's retina, and the glasses wearer's eyes.
The camera is 8 megapixels and has a 2.4 aperture lets in more light, has 60% more megapixels than the iPhone 4 and allows prints as big as 8x10.
Televison Camera
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.