Unmasking that sometimes confusing setting on your film camera.
Aspiring film photographers coming from a digital camera environment understand that the apparent sensitivity (ASA/ISO) of the digital camera can be changed “on the fly” depending on what the circumstances are. Changing that setting varies the sensitivity of the sensor.
This is a question I often see in forums: “Can I change the ASA/ISO on my camera while shooting the same roll of film?” No, it doesn’t work that way and below is an explanation of what this is all about.
On film cameras, the ASA/ISO setting is simply an adjustment that determines the sensitivity of the light meter (and this is the same for hand-held light meters.) The light meter then tells the photographer when the combination of shutter speed and aperture are correct for the film that is in the camera.
In order to develop the film correctly, the chosen ASA/ISO must remain the same for the entire roll of film. The film photographer can choose to vary the light meter setting from the box speed but I highly recommend just shooting box speed until well versed in how these systems work.
Happy shooting!
- gregory gammon / www.vinylfye.com
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