The Sunny 16 rule

The sunny sixteen rule is a very simple yet powerful tool to master when starting out learning about film photography or photography in general. It helps you to judge and see light without a light meter.

What is a light meter?

A light meter in a camera meters the average light in a scene and helps you to choose the proper settings for aperture and shutter speed according to the set iso or chosen film speed in your camera.

What is the photographic triad?

The photographic triad consist of ISO (ASA or film speed), aperture, and shutter speed. They are interchangeable to produce a proper exposure. The internal light meter in a camera can assist you in achieving the right exposure to compensate for the given light.

What is the sunny 16 rule?

The sunny 16 rule can be used to select the estimated settings for the aperture and shutter (and iso in digital) without the use of a light meter. It states that on a sunny day condition, using aperture or f stop 16, you can choose the reciprocal shutter speed to your chosen film asa (iso). For example, on a sunny day, use aperture f 16, at shutter speed 1/125 sec for an asa of 100. Similarly on a sunny day using aperture of f 16, chose a shutter speed of 1/250 sec for an iso of 200 asa. The rule applies to choosing the shutter speed at the very close asa (iso) setting in your camera. Shutter speed at 1/500 sec for a film speed of asa 400 etc.

The sunny 16 rule can be tweaked to a different aperture or shutter speed setting or vise versa. On your basic film camera, the aperture or f stop goes from f, 1.7 (wide open), 2, 2.8, 4, 5.6, 8, 11, 16, to 22 (narrow). Shutter speed from B (bulb), 4, 8, 15, 30, 60, 125, 250, 500, 1000. Each of these increments are what we call a stop of light. For example an f stop 5.6 to 8 is 1 stop of light. Film asa (iso), film stock or film speed can range from 64, 100, 200, 400, 800, 1600, 3200.

The sunny 16 rule states that on a sunny day condition (distinct shadow), use aperture 16. Partly cloudy (soft shadows), use f 11. Cloudy light condition (indistinct shadows), use f 8. Overcast day (no shadows) use f 5.6. Sunset/sunrise use f 4.

My favorite t-shirt (continue to be a favorite) back when I started learning about film in 2010.

Sunny 16 rule does not have to stay on a specific aperture to the light condition that we talked about. If you want to use f 5.6 on a sunny day to produce a little bit of blur or bokeh background, you want to increase your shutter speed 3 stops up. For example, if you were shooting in sunny (f 16) day, with a film speed of 100 (iso) and you want to use f 5.6, you will have to use a shutter speed of 1/1000 sec instead of the 1/125 sec. That is 3 stops of light from shutter speed 1/125, to (1) 1/250, (2) 1/500, to (3) 1/1000 sec. and so fort.