Sunny 16 rule.
A simple rule of thumb for taking photos in daylight without a light meter. The rule is quite easy to remember - if you’re taking a photo in bright daylight set the aperture to f/16 and set the shutter speed to be as near as possible to the same number as the film speed.
So if you’re using ISO 100 film, for example, set the aperture to f/16 and the shutter speed to 1/90 sec, since 90 is the closest shutter speed value to 100 on a typical camera.
If you want to use a different aperture calculate the number of stops away from f/16 you want to use and then adjust the shutter speed accordingly. For example, f/11 is one stop larger than f/16, so you’d need to decrease your shutter speed by one stop. So if you’re using ISO 100 film you’d set the aperture to f/11 and the shutter speed to 1/200 sec.
This rule works because the light output from the sun is a pretty constant value - the sun itself puts out a nearly constant amount of light at all times. Only precisely calibrated equipment can detect the light fluctuations of the sun.
cf. aperture, f stop, ISO, light meter, moony 11 rule, shutter speed.
Entry last updated 2002-04-03. Term 1198 of 1487.
Previous term: subtractive colour.
Next term: supplementary lens.