Film Speed – ASA

Newcomers to film photography often are confused by the different types of film and especially the different speeds of film.

When it comes to speed which is indicated as ASA (ISO when we’re speaking of a digital sensor) the basic rule is the slower the film speed the better the quality of the image.

So for basic everyday shooting on a sunny day a slow film speed of ASA 100 or ASA 200 is perfect. On cloudy days or nearer to sunrise or sunset a higher ASA of 400 to maybe 800 will yield better results but anything faster and you’re going to be dealing wth increased levels of grain.

Remember that film speed is part of the exposure triangle . Generally it’s the part of the exposure triangle that once set as indicated by the number on the film canister is not changed in mid roll.

The ASA setting is applied to the light meter (whether in the camera or an off-camera light meter) and helps determine the aperture and shutter speed settings that will result in a proper exposure for that particular shot.

On fully manual film cameras like Nikons FM2 or the older Nikkormat (if the internal light meter is working) you set the ASA and using the light meter needle or lights (depending on the camera) and then you set your aperture and shutter speed to either yield maximum or minimum depth of field as determined by the aperture or the ability of the shutter to stop action or allow for blur.

On semi-automatic old film cameras like the Nikon FE the camera sets the shutter speed depending on the ASA setting and the aperture you desire.

On fully automatic cameras the camera uses modes other than manual mode to produce a proper exposure automatically. While you’ll almost always get a properly exposed image it may not have the depth of field you wanted or the amount of blur or ability to stop action that’s called for.

Writing about this is way more complicated than using the exposure triangle and understanding how your camera, whether manual, semi-automatic or fully automatic actually operates.

Personally after shooting decades with Nikons I have returned to manual models (FM2, FE and Nikkormat) for my 35mm film shooting (all black and white that I develop and scan at home).

As I said with the exception of the aperture priority FE the FM2 and Nikkormat are fully manual film cameras. This means manual focusing lenses and manual exposure control. Often requiring a cleaning and a check by a camera technician these older film cameras are as capable as they were 50 plus years ago and are a great way to start shooting film without spending a lot of money. Carrying an external incident light meter is always a good idea when dealing with these older cameras.