In photography, the sunny f/16 rule is a method to obtain correct exposure without using a light meter.

The basis of the sunny f/16 rule are

1. Set your shutter speed equal to your film speed.

2. Set f stop according to the following table :

Aperture	Lighting Conditions	Shadow Detail
f/16	Sunny	Distinct
f/11	Slight Overcast	Soft around edges
f/8	Overcast	Barely visible
f/5.6	Heavy Overcast	No shadows