16
Concepts in Photography
Aperture
The aperture is one of the three factors that determine the exposure. The
aperture housing contains thin, metal plates that open and close to let
light through the aperture and into the camera. The size of the aperture
is related to the amount of light: a larger aperture allows more light and a
smaller aperture allows less light.
Aperture sizes
Minimum aperture Medium aperture Maximum aperture
Aperture opened slightly Aperture opened wide
The size of the aperture is indicated by a value known as the “F-number“.
The f-number represents the focal length divided by the diameter of the
lens. For example, if a lens with a 50 mm focal length has an f-number of
F2, the diameter of the aperture is 25 mm. (50 mm/25 mm = F2)
The smaller the f-number, the greater the size of the aperture.
The relative size of the opening in the aperture is indicated by the
Exposure Value (EV). Increasing the Exposure Value (+1 EV) means the
amount of light doubles. Decreasing the Exposure Value (-1 EV) means
the amount of light halves. You can also use the exposure compensation
feature to ne-tune the amount of light by subdividing exposure values
into 1/2, 1/3 EV, and so on.
+1 EV
F1.4 F2 F2.8 F4 F5.6 F8
-1 EV
Exposure Value Steps
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General
Weight and Dimensions
