'Temporary' 6x6 Wide Angle Camera

Discussion in 'Camera Building, Repairs & Modification' started by Steve Smith, Jul 15, 2009.

  1. Steve Smith

    Steve Smith Member

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    I have posted in other threads about a 6x12 format camera which I am building to use a Schneider 65mm Super Angulon lens which I acquired very cheaply.

    In order to asses the correct lens to film distance, I have temporarily mounted the lens on its modified Olympus OM helical focus mount to the body of a scrap 6x6 folding camera.

    The intention is to put a piece of ground glass at the film plane and focus on near and far points to see how close to the theoretical 70.5mm the back of the lens needs to be from the film for correct focus at infinity and also how close the focus scale is when used with this lens.

    The problem I have found is that this lens has so much depth of field, even wide open at f8, that I think I get a sharp image wherever it is set.

    Plan B is to assume the lens is o.k. at 70.5mm spacing and run a film through it taking some close up and distance shots at f8.

    Perhaps my original idea of a fixed hyperfocal lens was good after all!!


    Steve.
     

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  2. Christopher Walrath

    Christopher Walrath Subscriber

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    Just throwing it out there. Have you done any preliminary testing aiming the lens at a bright light source (ie. The sun) in a darkroom against the wall? You could determine focal lengths that way to get close and you should also be able to determine DOF with closer subjects in the same manner. Just a thought.
     
  3. Steve Smith

    Steve Smith Member

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    I have been using distant street lights (at night) and a sinlge wall light in my living room. I'm now fairly certain that I have it in the right place at the 70.5mm distance specified in the Schneider data on line. This would make sense as I wouldn't expect their data to be wrong.

    Wide open is only f8 on this lens which gives quite a bit of DOF which also equates to margin for error.

    I think a film or two will tell me what I need to know.


    Steve.
     
  4. Christopher Walrath

    Christopher Walrath Subscriber

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    Sounds like there's only one thing to do, huh.

    I would suggest a couple exposures at a close focus along a boldly printed measure so you can cheat in determining your close focus DOF.

    Good luck.