Advice for a 4x5 film holder that takes 120 film

I am currently planning to buy a pinhole camera, but the sizes are only in 4x5 format. What would be a nice 4x5 holder that takes 120 roll film? 6x6, 6x9, or 6x12 is what I want. And what prices do they usually go for?

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Take a look at the Calumet Roll Film Adapter.

http://cgi.ebay.com/Calumet-120-220...?pt=US_Film_Backs_Holders&hash=item1c1d183d17

There is a similar device made by Sinar , but it's Xtremely Xpensive !

Ron
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You can look online for older graflex roll film holders. They came in a variety of sizes and can be had fairly cheap. Some have problems with spacing and holding the film completely flat. Just make sure you get one for a 4x5 camera. They were made to fit other sizes of cameras as well as 4x5. How is the pinhole camera going to hold the film holders? Some of them use dowels or cams and this would require to use something like the calumet holder shown above. It will slip into a camera with either a spring back or cams. The graflex holders are of a different (and more common) design.