Well....You know.....I am thinking of buying a broken 3 1/4" X 4 1/4" double dark film holder that is broken on ebay for 8 bucks for research.
Somehow at this time I don't see much point in investing 8 bucks for this broken film holder to use for research to produce the "304" film back.
Perhaps you folks on this forum could show a bit more enthusiasm toward a project like this???
I have just finished one. I used the base plate from a film pack back, drilling out the pins that held the plate to the box that was meant to house the film pack. Adding a 3/16 thick frame of wood to the base, I could then glue on the Polaroid back from some version of the M4 or M3 copy cameras that were being thrown away all over the place a few years ago. Pretty good fit but I had some problems with light leaks. All solved now, I think. I went through a full pack of film testing it, though. So much for wild-ass guessing instead of careful craftsmanship.... Ah well, if you're going to be dumb you gotta be tough. I took the loss and moved on.
Focusing on a ground glass placed in the film holder allowed me to shim up the GG until that was also in focus. Not surprisingly, it needed just over 3/16th of additional distance from the mirror.
Now to go out and actually use the thing.
New findings, anyone?
I have an old Zeiss Ikon 3 1/4" X 4 1/4" pack film holder, rather sure it is of the 3 1/4" X 4 1/4" format, it measures exactly 3 15/16" wide, is that the correct width for this format's film holders?
The actual Polaroid CB-103 plastic pack film holder is wider than the old Zeiss Ikon film holder I have, it is 4 1/4" wide.
The proposed 304 holder looks to be one that will never slip under the ground glass spring back but be "grafloked" on to the camera.
One measurement that would really be good to have is the actual depth from the camera's back surface to where the film sits, could it be the same depth as a normal 4x5 film holder? this depth is easily sorted out by measuring a 3 1/4 X 4 1/4 double dark sheet film holder, measure from the face to the film plane, that is the depth measurement I need for now, hopefully the Polaroid Cb-103 being 4 1/4" wide it will still clear and be set back far enough to clear the grafloking tabs and mechanism to fit and such that the grafloking tabs can hold the 304 in place securely.
I am thinking of buying a 3 1/4 X 4 1/4 double dark sheet film holder off ebay for research.
Some how this project looks like the 304 holder may have to be made on a "Case by Case" basis if the concept will work at all, locating and using a darkslide could be problematical in that one may not be able to insert the darkslide in and out while the 304 is on the camera.
let me know what you think.
Regards, Steve I AKW