35mm lens aperture on 16mm film camera

[Andrius Zemaitis]

Dear friends, 

I have question regarding 35mm lens aperture on regular 16mm film camera. For example 35mm format lens aperture F2.8  is still same aperture on 16mm film camera ? If there is any degradation or increasion in terms of aperture? When I use a light meter do I need to calculate differently when I shoot with a 35mm format lens on a 16mm film camera? Or is it the same? 

Thanks.

Kind regards Andrius 

Edited September 24, 2021 by Andrius Zemaitis
i made some grammar errors

[Simon Wyss]

F/2.8 is f/2.8 on any camera. The focal length is different relative to the image size, so a 50 mm normal lens from a 35-mm. film camera is a moderate telephoto lens with 16-mm. film cameras.

[Karim D. Ghantous]

I'll add a brief comment. To help understand the concept of what a stop is, remember this: stops exist precisely so that you don't have to know anything about focal length or film format.

To expose, you only need to know ASA, T or f/- stop, and shutter angle or shutter speed. That's it. This system exists so that you can use the same exposure value for literally any camera and lens and film combination.

Without getting too technical, it only breaks down once you start extending the lens too far away from the film plane, or when you put certain filters in front of the lens. You need compensation in those cases.

[Patrick Cooper]

On 9/25/2021 at 1:46 AM, Simon Wyss said:

The focal length is different relative to the image size

Not really. The focal length doesn't really change. A 100mm lens will remain a 100mm lens regardless if it's mounted to a 70mm camera, 35mm camera or 16mm camera. What does change is the angle of view of the lens. Though I would agree that a 50mm lens (intended for a 35mm camera) would be considered a telephoto lens when mounted on a 16mm camera. 

And as to the original question, the film format has no bearing on what f stop or t stop you use. Just use your light meter like normal.