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Math
14-Sep-2010, 04:22
Hello all!
Let me start with saying I have no 8x10 experience, just 4x5. However, I do have some 8x10 film that would be fun to shoot! Now, I could go the pin-hole way, but I figured I might as well make it a box-camera with a lens, fixed-focus.
I'd have to carefully measure the distance, but it would mostly be portraits, head and shoulders.
Now, making it wouldn't be the biggest problem, I'll keep it simple and create it from a small cabinet or a high drawer, perhaps two glued together. It's really a one-time thing, taping the film in the back of the camera for exposure in the dark.
Now, what I wanted to ask is lens-related:
I have no lenses with full 8x10 coverage, except for perhaps the 20" Ross Xpress, but that's just a focal length too long right now. However, since I'll only be using it at a certain distance, coverage should be less of an issue. Say, 4 meter or 5 meter?
I have a few lenses that might cover 8x10 at these distances, but can anyone tell me if they really do? And what would a good distance be for shoulders and head portraits? What would, roughly, be the length from lens to film?
I have the following:
Krauss Zeiss Serie IIIa Protar / Anastigmat 196mm f9
Apo-Ronar 300mm f9
Or really maybe, a Beck Symmetrical ment for half plate, or a Rodenstock Eurynar 24cm f6.8?
I also have an Ernemann 360mm f4.5, but this is a last option as it's really too big to make it work and I couldn't use a shutter.

ic-racer
14-Sep-2010, 10:41
Some trigonometry can be used to figure your image circle coverage at 4 meters. At 1:1 the image circle will be double, and so on. At 1:1 the lens-to-subject distance will be = (focal length) times two. Do you know the image circle at infinity of any of your lenses?

In terms of angle of view on the 8x10 film, I'd try the 360mm. Even though it does not calculate out to a 'portriat length' lens at infinity, as you focus in to 4 meters, its angle of view will narrow. Though I'm guessing that at 4 meters you will still be getting more than just 'head and shoulders.'

One other solution is to use the 300mm lens on your 4x5 camera, I'm thinking that will be just about right for head and shoulders at 4 meters.

Armin Seeholzer
15-Sep-2010, 07:37
Hi Math

My 300 APO Ronar covers 8x10 even at infinity, so it should be fine at your distance with reserves!

Cheers Armin