Asanuma project camera – ground glass holder

The thickness of the ground glass holder is crucial to setting the ground glass at the plane of focus or film plane. I measured carefully the distance from the edge of a holder to the surface of a sheet of undeveloped film and got 3/16″. My glass is 3/32″ thick. So I planed the cherry to just a little proud of 9/32″. I laid out the the pieces and ripped the cherry to dimension:


Then I crosscut the pieces to final dimension and did a quick check for fit:


The pieces are joined with half lap joints cut with a horizontal router table. It’s not difficult, but more an exercise in transferring dimensions from piece to piece. Half lap cuts on pieces this narrow and thin, though, are a little hairy. I cut close to the lines and clean up with a chisel.

The final frame, dry fit:


Next step: Lay out and cut the rebate for the ground glass, then glue up the frame. The trick with the cuts will be the two stopped rabbets to be cut in the stiles. More on that later…


7 thoughts on “Asanuma project camera – ground glass holder

  1. This is fantastic stuff. I am attempting to build my first camera (all digital till this point in time) It is so much more complicated than I thought. I am just starting to cut wood for the rear frame and have been planning how the backs fit in etc. See what you have done here is really helpful and timely.

    I ground the glass at the end of last year and used a lot of the advice you gave in an earlier post. Anyway, just wanted to say thanks for sharing this information, it has been really helpful to me.


  2. So just to be clear and at the risk of sounding like a compleat idiot, the front of the ground glass (the side closest to the lens) is the film plane and needs to be at the same distance as the film? So it would be set 3/16 of an inch back from the opening? Not to that point yet but just want to have it clear in my mind.

  3. Paul –

    You need the lens side of the ground glass to sit precisely at the same plane as the film in the holder. To find this distance, I generally put an unexposed piece of film in a holder and VERY CAREFULLY measure the distance from the outer edge of the holder to the film surface. This is not a constant value consistent across formats, I don’t believe.. When you have that number, you make sure the inside of the ground glass is the same distance back from the insert.

    Hope this helps.

  4. That was my understanding, if not as clearly expressed as yours. *whew* This is tricky stuff but nowhere near what it would be without your examples.

  5. You probably know this already Scott but I recently go a supprise when I loaded a different brand 4×5 film holder and found the light trap spacing was different, here is a picture:
    Film holders
    Not a big deal to fix but a pain at the time in the field because of light leaks.

    • Hi, Tony –

      Good point. Thanks for making it. FWIW, I set the spacing on one of the narrower holders, so the older ones with the wider spacing will still ork on the ridge. Thanks for bringing this up, though.

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