Camera Tech: Aperture

Aperture-definition

Within a camera Aperture is the diameter of an opening within the lens which controls the amount of light that enters the camera, it is a measure of how much light enters the camera lens and how exposed the film and image sensor will be to that light. Aperture is contained within the lens and can be manually adjusted to be either wider or narrower, and this has an effect on how exposed the film is to light. Aperture is controlled by a device called a diaphragm which functions like the iris of the human eye and controls the diameter of the lens opening, increasing the aperture will make the opening smaller which in turn reduce the depth of field which limits how in focus an object or subject in the foreground is but puts the background in clearer focus, whereas reducing the aperture increases the depth of field so a subject far away will be in clear focus.

Aperture-Measurements

Aperture is measured in a ratio of focal length to effective aperture diameter, a lens usually has a set of f-stops which measures the diameter of the aperture. A higher f-stop number will usually mean a lower aperture diameter so the depth of field will be further, whereas a lower f-stop number will mean a larger aperture diameter and decrease the depth of field. The greater the f-stop number the lesser the light is exposed to the camera and vice versa.  

Aperture Scale Diagram