Setting camera ASA/ISO

[GrampaDoug]

Advertisement (gone after registration)

Stupid question time. When we set the ASA on our film cameras without a built in light meter does it actually do something to effect the timing of the shutter or is just there to remind us of what is in the camera?

Hope all are doing well and washing your hands!

Grampdoug

[Advertisement]

The Leica Q3 is available for pre-order at B&H Photo Video and Adorama

[TomB_tx]

Just a reminder, but lately I forget of what

[alb59]

It’s not for setting anything. Just a useful indicator of the film you’re using in case you forget.

[GrampaDoug]

Okay, the ISO indicator has no mechanical effect on camera’s operation. I use a M6 w/lightmeter, when changing the ISO setting it adjusts the measurement I see in the viewfinder, right. I’m having a serious senior moment combined with isolation. Will it ever end?

[250swb]

Adjusting the ISO on the dial of a camera with a built-in meter does affect the metering. The film speed (ISO/ASA), the shutter speed, and the aperture all work together and are integral to accurate metering. Inside the rear door of our M6 you will see gold electrical contacts that transfer the information you set on the dial to the meter in the camera, the amount of light coming through the aperture is detected by the meter (through the lens metering) and the meter along with the set ISO gives you a recommended shutter speed.

Only on a camera with no internal metering does the ASA/DIN (DIN is from yet another era) dial act simply as a reminder to use in guesswork or in setting a hand held meter.

Edited April 19, 2020 by 250swb