Mamiya Press Pinhole w/Mamiya 6x7 back --Help, Advice, Comments, Suggestions? Newbie!

Discussion in 'Pinhole Photography' started by jmarsh, Sep 25, 2012.

  1. jmarsh

    jmarsh Member

    Messages:
    5
    Joined:
    Jan 20, 2011
    Shooter:
    Medium Format
    Hello People,

    On a lark, I sent a Mamiya Press (front) body cap to be laser-drilled with a .24mm (that's point two four millimeters) pinhole, with the intention of using 120 film in a Mamiya 6x7 back.

    Question being, will a .24mm pinhole on a Mamiya Press camera with a focal length of --best estimate here-- 70mm have enough coverage to utilize all of a 6cm x 7cm negative? I've so far been unable to gather the info from internet searches.

    To repeat, it was on a lark --no research (stupidly?), little forethought-- and it's only now that I am wondering, have I simply created something useless and wasted money?

    Thanks for ANY help...

    joe
     
  2. Jim Jones

    Jim Jones Subscriber

    Messages:
    2,390
    Joined:
    Jan 16, 2006
    Location:
    Rural NW MO
    Shooter:
    Multi Format
    For a focal length of 70mm I'd use about a .275mm pinhole for optimum on-axis sharpness, or slightly larger to improve corner sharpness. If your pinhole is drilled directly in the body cap, it will illuminate only a small spot in the center of the image area. If so, the hole can be enlarged to accomodate a pinhole made in very thin material. Properly made pinholes have good wide angle coverage: 70mm should be no problem on your camera. Two sites with much information on pinhole photography are http://www.f295.org/Pinholeforum/forum/Blah.pl and http://home.online.no/~gjon/pinhole.htm
     
  3. summicron1

    summicron1 Subscriber

    Messages:
    1,944
    Joined:
    Jul 28, 2010
    Location:
    Ogden, Utah
    Shooter:
    Multi Format
    yeah, you want the hole in really thin metal so that the light can enter and exit the hole at an extreme wide angle -- if it is there is practically no limit -- my ZeroImage 4 by 5 pinhole camera gets excellent coverage with a pinhole distance-to-film of 50 mm and even does ok at 25, although vignetting is rather extreme at that distance.

    But I'd give it a shot in any event, the plastic in ur lens cap may be thin enough to give you good coverage with a .250 mm pinhole. 70mm is pretty far away.
     
  4. geoferrell

    geoferrell Member

    Messages:
    81
    Joined:
    Feb 18, 2008
    Location:
    McKee, KY 40
    Shooter:
    Medium Format
    On the Mamiya Universal press and the pinhole on a body cap, what type of results did you get? I've got one too and have been studying drilling a hole in the body cap and putting a pinhole on. I tried that with another MF camera and got interesting results. I used aluminum from a pop can and made a pinhole and the results seemed creative. Am wondering about the Universal, the body cap I have extends and is not level with the placement of the lens mount.
     
  5. bsdunek

    bsdunek Subscriber

    Messages:
    1,351
    Joined:
    Jul 27, 2006
    Location:
    Michigan
    Shooter:
    Multi Format
    I drilled a Mamiya body cap 1/2 in. and used a very thin piece of tooling copper with a 0.40mm hole cemented behind it. I use the shortest extension tube, which gives a more or less "normal" view and covers the 6X7 format just fine. I haven't tried the cap directly on the body for a more wide angle look. Should make a smaller hole for that I guess.
     
  6. John Koehrer

    John Koehrer Subscriber

    Messages:
    6,371
    Joined:
    Apr 3, 2004
    Location:
    Montgomery,
    Shooter:
    Multi Format
    That's the better method, large hole in the cap and a metal insert/section for the actual pinhole.