Choosing the Right ASA
Problem: You are still taking pictures with your faithful film camera and haven’t moved on to digital. Given the many different film types, what kind should you use? It really depends on your desired end result. If you want to give shows to your friends, then you should pick slide film. If you’re working on a photo album, then print film is generally best. Now, which ASA will work best? ASA (film speed) determines how much light has to be let into the camera to make a correct exposure. Controlling factors on allowing light to hit the film are shutter speed, f-stop, and available light. The basic rule on shutter speed is this: the more motion (that either you or the subject has), the faster your shutter speed should be. F-stop is the aperture control in your lens. A fast lens will have an f-stop of 2.8 or lower and may allow you to use a lower-speed film. If your lens has a maximum opening of f-5.6 or f-8.0, then you have a slow lens and will need a higher ASA film. Lighting conditions will also combine to determine film speed. Generally, low light requires ASA 400 or higher. Bright sun conditions will allow you to use a lower-speed film. Another consideration is that the higher the ASA, the lower the quality of the photo.
Solution: If you are shooting on a moderate to bright sunny day, use a lower ASA of 100. If you are photographing in a dark canyon on a cloudy day or during sunrise/sunset, move up to a 400-speed film. These rules apply when you are trying to capture moving subjects and are using a fast shutter speed. If you are shooting landscapes or scenics with no action, in low light, or with your camera on a tripod, then you can use a slow shutter speed along with a low ASA film. When hand-holding the camera, it is best not to use a shutter speed of less than 125th of a second. So when you go off on your trip down the Grand Canyon, you should take some 100- and 400-speed film. The majority of it should be 100 ASA. When you walk into one of the deep side canyons, use 400 so you won’t have to lug along a tripod. And don’t rely on the little flash on your camera to light the cave.
Example: I use Fuji Provia 100F and 400F. The majority of film that I shoot is Provia 100F because it yields the sharpest and best color-balanced results. In low-light conditions, I switch to 400F. It still gives me most of the sharpness and increases my aperture and shutter options. This photo of Tao Berman was taken with Provia 100F in moderate light at 1,000th of a sec at f2.8. The film is tack sharp and filled with detail.
Jock Bradley is a veteran paddlesports photographer who lives in Seattle.