Need lens advice

[aopie]

I'm shooting tintypes on a J.T. Chapman 19th Century full plate camera (6.5"x8.5" max). I want to find the right lens to allow me to do full (head to toes plus some room) double portraits. I have tried all the medium/large format lenses I have and they all seem to need to come closer to the film plane than my camera will allow - they won't focus as far away as I need to get the field of view I want. Can anyone advise as to lenses that would give me the viewing area I need without coming so close to the film plane? Is it particular mm of lense that would do this or is it more specialized than that? I don't mind some fall-off at the edges. If it just isn't possible to get what I want with this camera I'll probably work on getting an 8x10 but I would like to make this one work if I can.

J.T.Chapman camera specs:
Minimum bellows extension: 8.5"
Maximum bellows extension: 18-19"

I've tried these lenses (what I happen to have):
Textronix Ilex 3 inch Oscillo-Paragon 75mm 1:0.85x f1.9
Kodak Ektar 203mm f7.7
Caltar II-E 150mm f6:3
Ross Rapid Symmetrical 9x7 (brass barrel lens - approx 10.5" focal length - to film plane)

Thanks!!!
Alexandra

[Bob Salomon]

Can you move the camera further from the subject?

[aopie]

I can move it far enough that I should be able to get what I want - say between 11 and 16'. But with all the lenses I have my subject was totally blurry that far away.

[aopie]

Update. I have figured out how to move the lens closer to the film plane - I missed a basic function that allows the lens board & bellows to slide closer. So, I am now able to focus on a standing figure at a reasonable distance to make a sitting portrait - takes longer distance to allow standing portrait and that's where another lens would be great. I would still very much appreciate advice on lenses for shooting standing portraits with a distance to subject of 10' if possible.

Thank you,
Alexandra

[Jim Galli]

I would start with that Ross lens. It should work perfectly on your camera. Not so very fast though.

[Leigh]

Hi Alexandra,

The easiest way to work out bellows extension is to use the magnification ratio M = image size / subject size.

If your subject is 72" (6') tall and you want its image to be 6" on film, the ratio is 6:72, so M = 6/72 = 1/12.

The distance from the lensboard to the film is approximately focal length*(1+M).
For the 1/12 ratio that equals focal length*1.083.

That's pretty close to the infinity focus position for the lens.

- Leigh