F-stop (also f-number)

F-stop is the light gathering ability of a lens (known as a camera lens aperture setting) and is indicated by an f-stop number. Using a smaller f-stop number results in a greater amount of light passing through the lens, as well as a shallower depth of field. While the shutter speed affects the duration of light hitting the sensor, the aperture affects the amount of light hitting the sensor. To put it simply, the aperture is the part of a lens that dictates how much light is let through to the sensor – if it’s wide open, lots of light gets through. If it is closed down, not much light gets through. In essence, it performs the same as the pupil of an eye. If you are in a dark room, the pupil is open; in sunlight, the pupil is small.

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For more information please also see Aperture , Auto Iris Lens , and Depth of Field.

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