Exposure basics
Three settings decide how much light reaches the film.
- Aperture (f-number): how wide the lens opens. Smaller numbers let in more light and blur the background.
- Shutter speed: how long the shutter stays open. Fast speeds freeze motion; below about 1/60 s you'll need a steady hand or tripod.
- ISO: the film's sensitivity, fixed for the whole roll.
The Sunny 16 rule
In bright sun, set the aperture to f/16 and the shutter speed to 1/ISO (for ISO 200 film, 1/250 s). Open up one stop for slight overcast, two for heavy cloud.
When in doubt, add light
Colour negative film handles overexposure well but loses detail when underexposed. Slide film is the opposite: expose precisely.