Sunny 16 rule

Sunlit subject shot on a digital camera set to ISO 100, exposed at f/8 at 1/400 second which is the same exposure value as f/16 for 1/100 second, the recommended "sunny 16" exposure

In photography, the sunny 16 rule (also known as the sunny f/16 rule) is a method of estimating correct daylight exposures without a light meter. Apart from the advantage of independence from a light meter, the sunny 16 rule can also aid in achieving correct exposure of difficult subjects. As the rule is based on incident light, rather than reflected light as with most camera light meters, very bright or very dark subjects are compensated for. The rule serves as a mnemonic for the camera settings obtained on a sunny day using the exposure value (EV) system.

The basic rule is, "On a sunny day set aperture to f/16 and shutter speed to the [reciprocal of the] ISO film speed [or ISO setting] for a subject in direct sunlight."[1]

  1. ^ Bernhard J. Suess (2003). Mastering Black-and-White Photography. Allworth Communications. ISBN 1-58115-306-6.