Where to buy large dichroic mirrors?

wtburton

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I have a 5x7 Devin Tricolor camera, and while I have not finished repairing it (it needs new plate holders and a proper lens), I thought if such a thing was possible for 35mm film, as I have an enormous amount of bulk 35mm B&W. I saw on a thread posted awhile ago that somebody recommended Dichroic mirrors because they do not cause light loss like the semi transparent mirrors. I have only been able to find small (1 inch) mirrors for sale, and was wondering if there was a way to get 2x3 sized Dichroic mirrors (maybe a bit bigger?)

You would need one that reflects blue, transmits green/red, and then one that either reflects red and transmits green, or reflects green and transmits red.
 
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wtburton

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figuring this all out for myself as I go. 45 degree reflective filters are the right thing needed. I did the math and when put at a 45 degree angle, the 50x50mm square actually becomes a 50x35.36mm rectangle! To visualize this, I made a simple cad model




yeah the design of the mount is horrible, lol. I will go though and do some serious work on making tricolor camera design. of course, the first film holder (probably blue?) should be pushed back a little bit to make up for the gap in-between the two 45 degree filters.

Unfortunately, this means that 120 is out of the question unless larger filter's in the 4inch size range could be found. This however, leaves a lot of space to work with as a 35mm system? No idea about the lenses yet, whatever lens used would most likely need to cover medium format or more, the focal length will at least be ~60mm?
 

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cramej

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warrebphoto said:
Unfortunately, this means that 120 is out of the question unless larger filter's in the 4inch size range could be found.
Click to expand...

But you aren't putting the mirrors at the largest point in the path so you don't need mirrors the same size as your film.
 
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wtburton

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cramej said:
But you aren't putting the mirrors at the largest point in the path so you don't need mirrors the same size as your film.
Click to expand...

I guess that is true, but I wonder why all older one shot camera's are made with mirror's in this orientation. I know the Devin tricolor I have certainly looks that way.
 
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wtburton

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Interesting! Its worth a shot. I found a large one some guy ripped out of a projector, and im gonna get it. I have some really tiny lenses to play around with. I might actually need to get a smaller cube. This seems like it would allow for wider angle lenses, but finding a way to fit three strips of 35mm side by side is gonna be a challenge! unless of course, I could somehow wrap a single strip around the cube? That might be the way to go. A plastic holder with curves on the corners as well as the image frame, with plenty of sprockets or rollers?
 

maltfalc

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