Certified Professional Photographer (CPP) Practice Exam

The Sunny 16 rule is a guideline for photographers that helps to determine correct exposure settings in bright sunlight conditions. It suggests that on a clear, sunny day, the correct exposure is achieved with an aperture of f/16 and a shutter speed of 1/ISO for the film speed or sensor sensitivity being used. This means that if you are using ISO 100, your settings would be f/16 at 1/100 second.

In this case, f/16 is used as a starting point because the rule is based on the amount of light available in bright sunlight, which reaches an intensity that allows for this aperture to provide a balanced exposure. As light conditions change, photographers can adjust their aperture and shutter speed accordingly while maintaining the correct exposure.