Aperture setting in photography

Aperture is a setting that determines the amount of light reaching the surface of the sensor or film. It is located inside the lens. Aperture is made up of a number of very thin blades which form a circular opening and are able to change the diameter of this circle by fanning in or out.

When the aperture is set to f1.4, for example, the amount of the light reaching the sensor or film will be much greater then if it would be set to f22. So, the smaller the number, the larger the aperture and vice versa. Each lens has a set number of apertures it can do, generally it will be something between f4 and f32, this is determined by the design of the lens. There are lenses capable of apertures as wide as f1.2 and as narrow as f64. The aperture values in between the maximum and minimum aperture are adjustable. These are called stops, each stop changes the exposure by half. This way it is possible to control the exposure.

Other thing aperture controls is depth of field, if the lens is focused on a close distance and the aperture is set to widest setting then the image will come out with blurred background and foreground, if the aperture will be set to narrowest setting then of the image will be in sharp focus, this distance in front of subject and behind is the depth of field. There are other factors that contribute to the depth of field, such as the distance from lens to subject, from subject to background distance and the focal length of the lens, all of these factors, plus the aperture determine the depth of field of the resulting image.