An important part of making sure that your film photos turn out well is choosing the appropriate ISO film. A film’s ISO is a measurement of how sensitive the film is to light. The lower the ISO number, the less sensitive a film is to light and the higher the ISO number, the more sensitive the film is to light.
The most common ISOs are 100, 200, 400, and 800. Some black and white films can go as high as 3200 ISO, but most popular color films will be 800 or less.
Bright Sunlight
For photographing in extremely bright conditions (think middle of summer outdoors or in the desert), we recommend a slower speed film. ISO 100 or 200 would be a great choice!
If you try and shoot a faster film in bright sunlight (such as ISO 800) you will most likely find that your camera will struggle to compensate for all of the light. You run the risk of having over exposed images.
Dusk, Foggy Conditions, or Indoors
For times of the day when you do not have strong, direct sunlight, we recommend ISO 400 film. This is an exceptionally versatile film that works well in mixed lighting conditions. It can easily get a nice exposure during darker parts of the day such as dusk, while also being able to handle normal afternoon light.
If you are ever in doubt, ISO 400 is the way to go.
Low Light
For nighttime photography your best bet is ISO 800 film. This film is fast enough to properly expose an image in darker situations. If you try anything below ISO 800 you run the risk of getting either a blurry photo or a muddy, underexposed one.