What is the sunny 16 rule?
The sunny 16 rule is 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 reciprocal (1 / x) the film speed. So if you re using ISO 100 film, for example, you would set the aperture to f/16 and the shutter speed to 1/100 sec. However, since most cameras don t have a 1/100 sec setting you would set it to the closest shutter speed, which is 1/90 sec. 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 from many locations on the Earth because the light output from the sun is a pretty constant
