Sunny 16 or F16 Rule. Exposure cheat sheet

On a sunny day set aperture to f.16 and shutter speed to the 1/ISO film speed for a subject in direct sunlightlight

Aperture

Shutter speed

Light conditions

Shadow detail

F.16

Use the closest value

to the ISO  of your film

1 / ISO

Sunny

Distinct

F.11

Use the closest value

to the ISO  of your film

1 / ISO

Slightly overcast

Soft

F.8

Use the closest value

to the ISO  of your film

1 / ISO

Overcast

Barely visible

F.5.6

Use the closest value

to the ISO  of your film

1 / ISO

Heavy overcast

No shadow