what is aperture

Aperture is an opening in a lens through which light passes to enter the camera. It is one of the three pillars of photography, along with shutter speed and ISO. The aperture and focal length of an optical system determine the cone angle of the bundle of rays that come to a focus in the image plane. In photography, the aperture is calibrated in f/stops and is generally written as numbers such as 1.4, 2, 2.8, 4, 5.6, 8, 11, and 16. Lower f/stops give more exposure because they represent larger apertures, while higher f/stops give less exposure because they represent smaller apertures. The size of the aperture can be adjusted either on the lens itself manually or through the cameras electronics. Aperture can add dimension to photos by controlling depth of field, which is the zone of acceptable sharpness in front of and behind the subject on which the lens is focused.