Fujinon 300mm F5.6 Lens and Mounted Board

Discussion in 'Large Format' started by 25asa, Sep 23, 2020.

  1. I just received this lens off a Japanese seller on Ebay. I didn't notice it in the pictures, but this lens is mounted to the Toyo lens board via 4 screws instead of 1 retainer ring. Is this common practice? Getting those nuts off will be difficult to start. My concern is this will be mounted to a wood 6x6 board and the thickness of the wood may cause issues with the studs. I dont think the studs look that long, as the Toyo board is quite thin. Would a retaining ring even work mounted to an Ansco 6x6 lens board? Im concerned I may not be able to remount this on my needed board. What does anyone suggest? Also if it was necessary, could the studs even be removed? I wonder if my wood lensboard would need the thickness around the hole reduced to get this to work?


  2. The Ansco lensboard is extremely thick. I dont know if mounting would be possible with my combo?

  3. Got some info from another site. Apparently its mounted on a flange. Im told all I'd need is longer screws. What screws would you suggest for the Ansco wood board?

  4. The Ansco lens board is 1/2" thick.
  5. This mount is quite common (e.g. Shanel shutters). The flange is attached to the lens board, here with nuts and bolts, or directly screwed to an aluminum board, without nuts.
    You need to move the flange to your lens board. I don't know the size of the hole in your Ansco lens board, the flange should fit.
    If it doesn't fit (remove the flange and measure it), you need either to get the right sized lens board, or to remove excess of material in the one you already have. It can be done grinding with a file (very likely you'll destroy the lens board) or machining it with proper tools (the right way).
    Then, once after the work is properly done, you can 1. Attach the flange in the same way (nuts and longer bolts), or 2. Attach the flange to the board with screws (I assume the board is a wooden one, so wooden screws and hardener are needed), or 3. Glue the flange to the board (with epoxy, it may seem the easiest way, but it can end up being the most sloppy, too).
    Another option (most recommended) is to send it to a professional machinist, S. K. Grimes use to be a classic reference.
    Last edited: Sep 23, 2020
  6. The length of bolt is the least of your worries.
    You don't show the rear section of the lens, but there's a strong possibility that the thickness of your new lensboard will prevent the rear 'half' of the lens from fully screwing onto the front section - unless a suitable recess is milled into the board.

    I/2" is pretty thick, even for a wooden board. I'm wondering if this is standard or necessary.

    I'm now wondering if you have the rear section of the lens? Or if it's missing.
    Last edited: Sep 24, 2020
    ajkocu likes this.
  7. The lens flange was attached at the back of the lens in front of the lens board. The back lens is no wider then the ring attachment, so the back lens should slide right through the hole easily. I don't forsee any issues with this setup at this point. Again the flange screws in front of the lens board at the back of the shutter section. Yes I have the rear lens, as I took it off the remove everything.
  8. OK. Well at least you have the complete lens.

    Pictures of the Fujinon W show the back section flaring out from the 'waist' where it joins the front section. Just like a Nikkor W, Sironar or Symmar.

    The 1/2" lensboard thickness concerned me because I've had the issue of even a 1/4" thick board preventing the two halves of a lens fully mating. In my case the mounting ring was pushed too far back by the panel thickness, and needed a rebate cutting. It looks like the board itself might collide with a widening rear lens section in your case.
  9. You get 4 small wood screws, unscrew the lens flange from the Toyo board. Unscrew the shutter from the flange. Screw the flange to the FRONT of the Ansco board with the 4 small wood screws, alternatively you can screw the shutter back onto the flange, rotate the shutter till the scales are on top, mark thepositions of the holes in the flange on the Ansco board. Drill holes through the board where the marks are. Use 4 long machine screws to mount the flange to the board and remount your lens to the flange.
    Takes less time to do it then to read this.

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