The basic rule is, “On a sunny day set aperture to f/16 and shutter speed to the [reciprocal of the] ISO film speed [or ISO setting].” For example:
- On a sunny day and with ISO 100 film / setting in the camera, one sets the aperture to f/16 and the shutter speed to 1/100 or 1/125 second (on most cameras 1/125 second is the available setting nearest to 1/100 second).
- On a sunny day with ISO 200 film / setting and aperture at f/16, set shutter speed to 1/200 or 1/250.
- On a sunny day with ISO 400 film / setting and aperture at f/16, set shutter speed to 1/400 or 1/500.
Emma from Expert Photography got in touch and provided a link to a much more detailed article about this, check it out here: