Need 90 to 100mm image circle short FL lens.

Discussion in 'Camera Building, Repairs & Modification' started by Loose Gravel, Jan 5, 2007.

  1. Loose Gravel

    Loose Gravel Member

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    I'm looking for a short focal length lens in shutter with an image circle about 90 to 100mm. I'd like to build a camera that shoots the whole circle onto 4x5 film. Lens could be fisheye type or rectilinear. I'm not sure what to look for. Were there Polaroid cameras with short focal length lenses or maybe a Graflex 23 lens? Any ideas?

    Thanks.
     
  2. Nick Zentena

    Nick Zentena Member

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    How short? Some of the Mamiya RB lenses can cover 6x8. Not sure how many mm that would be. I'm also not sure how you'd trip the lens.
     
  3. jimgalli

    jimgalli Subscriber

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    I have some cells laying around here somewhere that are 75mm cover 6X6 at infinity and fit any Copal 1 shutter. I don't have the sutter, just the cells. Tominon f4.5 tessar type. If you have an ordinary 210 you could share the shutter. $22 and a little shipping.
     
  4. dmax

    dmax Member

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    Loose Gravel,

    I'd highly recommend a 65mm Mamiya from their old 2x3 line - Mamiya Press or Mamiya Universal. I have 65 Mamiyas mounted onto purpose-built 6x9 bodies, and they're superb lenses. They originally come in a Seiko shutter (very similar to a Copal 0) mounted in a largish (read as bulky and heavy) focusing helical. I disassembled the units and remounted the lens and shutters into regular helicals. The 65 Mamiyas cover at least 100mm across the 6x9 diagonal. This should give you a neat circle on 4x5.

    The 75 mm version, either from the Polaroid 600E line or the Mamiya line (same lens, different mounts) just barely vignettes at infinity when forced into service for 4x5 work. In other words, it has a larger image circle than what you probably want. Another superb lens though.
     
  5. Ole

    Ole Moderator Staff Member Moderator

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    See if you can find an 80 or 90mm Tessar lens - off an old folder or something, or perhaps an enlarger lens. That should do the trick.
     
  6. epatsellis

    epatsellis Member

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    IF you have an RB already, making a lensboard and tripping the shutter is trivial, all you need is a junk RB (KEH has AS-IS ones for <$20) once you look at the back of the lens, and cycle it a few times, it's obvious (hint: cycle it with the lens im MLU modewith a cable release attached). I'm currently working the design out in my head for a 6x7 monorail that will have the option of using RB lenses, as well as standard view camera lenses, and standard RB backs. Note that several of the lenses, from 90m to at least the 150 SF illuminate(haven't checked sharpness yet) 4x5, with some wiggle room.


    (I've got a good stash of Toy/Omega View camera parts for this project, as well as a Toyo 810D (using fixed bellows, standard Toyo 45D front standard, light and relatively cheap)

    erie
     
  7. Loose Gravel

    Loose Gravel Member

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    Thanks everyone. I was about to let this project die, but now there is new life.

    --LG--
     
  8. ondebanks

    ondebanks Member

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    Could you please explain exactly what happens, rather than give hints? I would really like to know whether one can cock an RB67 lens when the rear of it is inaccessible (because it's on the inside of the lens board/bellows). I don't own an RB67 lens and I don't want to have to buy one simply in order to find out! But if you can confirm that RB lenses can be cocked from the front when used on a LF or Press camera, then I would be interested in adapting them onto my Mamiya Press.

    Cheers,
    Ray
     
  9. Steve Smith

    Steve Smith Subscriber

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    The RB lens has two sockets for cable releases. One activates the mirror up, the other trips the shutter. In order for the mirror to go up, the shutter has to close which is also what the first cable release does.

    Does it also cock the shutter though?


    Steve.
     
  10. epatsellis

    epatsellis Member

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    Sorta,
    the firing/cocking cycle is totally controlled by the rotation of the cocking ring on the body, give me an hour or two and I'll take some pics and post a quick page on my server detailing it.


    erie
     
  11. epatsellis

    epatsellis Member

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  12. ondebanks

    ondebanks Member

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    Great, keep us posted when you complete the page. So far you've shown how it works with the lens unmounted...what I'm dying to see though is how to rotate the cocking pins when the lens is mounted and you can't get at the back of it!
     
  13. epatsellis

    epatsellis Member

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    well, a rough first draft is now up, same link, with a link at the bottom to the next page. I need to get to my parts bodies to add some pics, but the ones that can be taken without trashing a body are there.


    erie
     
  14. epatsellis

    epatsellis Member

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    must've shocked him how easy it is....he's speechless...


    erie