aperature

The word aperture refers to the opening in the camera lens that allows light to pass through to the film. On a manual camera, the aperture can be physically changed from a more narrow opening allowing a greater depth of field and less light to pass through the lens, to a broader setting allowing much more light to pass through to the film.

Aperture settings on cameras have to be balanced with the shutter speed - or the time that the shutter opens during the taking of the photograph. If your aperture is too wide, allowing a lot of light through to the film, and you shutter speed is slow enough to also allow light to pour in for a long time, your picture will be overexposed. The opposite is true as well in the case of a narrow opening and a very rapid shutter speed. The image, in this case, will be underexposed. With daylight film on a sunny day, the average aperture setting on a manual camera is f 8 with the shutter speed of 1/60 of a second or 1/125 of a second.