The f/16 rule: photographing without a light meter

Before modern cameras, photographers estimated exposure by eye. The f/16 rule still allows one to do without a light meter in many situations today.

The principle is simple:

☀️ In good weather, in full sun:

• Set your camera to f/16
• Choose a shutter speed close to the film sensitivity

For example:

• 100 ISO film → 1/125 s at f/16
• 200 ISO film → 1/250 s at f/16
• 400 ISO film → 1/500 s at f/16

This exposure serves as your starting point.

Then, adjust according to the light

☀️ Bright sun → f/16

🌤️ Overcast sun → f/11

🌥️ Bright overcast sky → f/8

☁️ Overcast sky → f/5.6

🌳 Shade or end of the day → f/4

Each time you open the aperture by one stop (from f/16 to f/11 for example), you let in twice as much light.

Why learn it?

• Understanding exposure
• Photographing with cameras without a light meter
• Continuing to photograph even if the battery is dead
• Gaining speed in the field

The f/16 rule is not magic, but it is often surprisingly accurate. With a bit of practice, one can quickly estimate light with a very low margin of error.

A good reason to lift your eyes from your light meter and start observing the light again.

Here are some photos taken with a Photavit camera from 1939 :