Editing F-number (section)

=== Sunny 16 rule ===
An example of the use of f-numbers in photography is the ''[[sunny 16 rule]]'': an approximately correct exposure will be obtained on a sunny day by using an aperture of {{f/|16}} and the shutter speed closest to the [[Multiplicative inverse|reciprocal]] of the ISO speed of the film; for example, using ISO 200 film, an aperture of {{f/|16}} and a shutter speed of {{frac|200}} second. The f-number may then be adjusted downwards for situations with lower light. Selecting a lower f-number is "opening up" the lens. Selecting a higher f-number is "closing" or "stopping down" the lens.