Lens Coverage on homemade polaroid/20's plate camera

[michaelbsc]

Hmm, but if his FL is doubling (we could all hope to be so lucky)

Well, it only works that way on a symmetrical lens. Other designs behave differently, and in ways that I don't understand.

then he's gonna run out of bellows it sounds like.

Oops. Didn't think of that.

[himself]

just wondering if anyone knows what sort of coverage I can get out of a Carl Zeiss Jena Tessar 1:6.3, 120mm.

thanks

[Dan Fromm]

just wondering if anyone knows what sort of coverage I can get out of a Carl Zeiss Jena Tessar 1:6.3, 120mm.

thanks

Depending on whose exaggerated coverage claims you believe, anywhere between 138 mm (60 degrees) and 168 mm (70 degrees). 60 degrees is much more likely.

[himself]

60 degrees is much more likely.

thanks for the info, but that's actually bigger than I've been previously told, so maybe I should just ask the guy if I can try it.

[himself]

for those of you that still may have a small interest in what's going on here - the lens in question has now been moved to the home-made view camera I have (that can be seen here http://www.apug.org/forums/forum147/...please-32.html), so instead of starting a brand new thread I thought I'd hijack my own and change course a little.

So the new camera shoots pretty much any size up to 4x5, but as you can imagine the lens won't come anywhere near that, but because the lens is on a camera with a longer extension than the plate camera some options have opened up:

the thought of buying a new lens crossed my mind for all of the amount of time it takes to do an ebay search for large format lens, so I decided to go back to some of the suggestions I already had.

taking one of the rear cells out of the shutter gives me more than enough coverage for any movements I have, but the image quality is poor and there doesn't seem to be much light getting through.

so what I've now discovered is that if I tape the dipoter from holga-polaroid back to the lens, the focal length increases (not as much as taking a cell out) without any lose of quality, and so, but here's the thing - so does my image circle, now that can't be right can it?

can turning my 105mm lens into a 150mm with the aid of a small plastic lens actually increase my image circle enough that I can swing and tilt to my hearts content, maybe not on 4x5 but certainly on 3x4 and all at infinity... I can scary believe it.