EN: F/stop


A fraction which indicatesthe actual diameter of the aperture: the f represents the lens focallength, the slash means divided by, and the word stop isa particular f-number; for example, with a 50mm f/1.4 lens, the actual diameter ofits maximum aperture is 50mm divided by 1.4 or 35.7mm; at f/2, the diameter becomes50mm/2 or 25mm; at f/2.8, the aperture is 50mm/2.8 or 17.9mm across; as the numericalvalue of the f/stop increases, the aperture decreases in size.
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