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Definition of f-number

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A Simple Explanation of F-Stop Numbers

Our Eye’s F-Stop👀 Ever wonder what the f-number of your eyes are? It can easily be calculated using the human eye’s focal length (~22mm) and physical aperture size. Computing the f-number of the human eye involves computing the physical aperture and focal length of the eye. The pupil can be as large as 6–7 mm wide open, which translates into the maximum physical aperture. The f-number of the human eye varies from about f/8.3 in a very brightly lit place to about f/2.1 in the dark. The presented