Hi- I'm new to large format, having used medium format and 35mm for quite some time. I am wondering if anyone can help me- Do I need to have longer exposure times for large format, or go with larger apertures? If I use a handheld light meter, do I need to do any adjustments? It just seems like I need to expose longer, but maybe I'm just incorrect.
I am not referring to bellows compensation, which makes sense to me. I am just wondering if the exposure times/ f-stops are the same as medium format and 35mm?
The reason I ask is that if I compensate 1 stop on my Hasselblad 6x6 over my 35mm, I get great results. Wondering if the same is true, or even to a greater extent for large format...
Thank you all in advance- this is a rad community.
There is a reason that large-format cameras are usually seen mounted on tripods. That's because the exposure times most used are usually longer than those commonly used on medium and small-format cameras. The main reason is that in order to get a similar depth-of-field on LF film, you have to use a smaller aperture than on a smaller format. The general rule is: the larger the format, the smaller the aperture needed for a given depth-of-field. In theory, you could shoot at the same aperture and shutter-speed combination on any camera given the same film. Most, however, usually want a certain amount of depth-of-field, which requires stopping down. Additionally, most large-format lenses widest apertures are in the
f/5.6-
f/8 range; you need heavy and more expensive "specialty" lenses to get even
f/4 and
f/1.8 is practically unheard of in LF. Plus, shooting wide-open with many LF lenses can introduce aberrations (most LF lenses aren't designed to be used wide open, but are optimized for
f/16-
f/22) in addition to the very shallow depth-of-field.
I don't know where you got the idea that you need to compensate one stop for medium format over 35mm... The same films are available for both formats (and for LF to a great extent) and the amount of light needed to expose a given film is the same regardless of format. The idea that you have to compensate exposure for different formats is incorrect. A hand-held meter should give you the same, or at least close, readings as an in-camera meter if used properly. If there is a significant discrepancy between your in-camera meter and your hand-held meter, then one or both are out-of-whack.
The fact that you get "great results" when exposing a stop more for your MF film can be attributed to a number of things: B&W film is very forgiving of overexposure, maybe you are slightly underexposing your 35mm film without knowing it, etc., etc. Ideally, your meters would agree, and you would be using the same, correct, exposure for all formats. Aperture gets chosen for desired depth-of-field.
Best,
Doremus