cocking the wollensak dumont 75mm f1.9 shutter?

Discussion in 'Large Format Cameras and Accessories' started by djkloss, Jun 16, 2013.

  1. djkloss

    djkloss Subscriber

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    how do you cock the shutter in a wollensak dumont 75mm f1 9 oscilliscope lens? There is no way of cocking the shutter that I can see. I can see the blades. It looks as though it were half cocked. i like the wide aperture, just can't figure out how to make it work. Some guy on ebay has one for $2000, marked down to $1700. Go figure!???

    thanks,
    Dorothy
     
  2. Dan Fromm

    Dan Fromm Member

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    It is a self-cocking shutter. Pressing the shutter release lever first cocks the shutter and then releases it.

    Your shutter needs service.

    Oh, and by the way, you really should unscrew a cell and check how far the diaphragm opens. Since the shutter blades won't open fully, the rear cell is the one to unscrew 'cos the diaphragm is behind the shutter blades. You're in for an unpleasant surprise; wide open the diaphragm opens to only around 25 mm.
     
  3. djkloss

    djkloss Subscriber

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  4. pgomena

    pgomena Member

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    The high price must be a sucker's price. Those particular lenses have very limited applications and can't be used for general photography. They are intended only for photographing signal traces on an oscilloscope. They might be used for extreme close-up photography, but they apparently have an odd field of sharpness that matches the curve of an old-fashioned 'scope's display. Nowadays they are most useful as paperweights.
     
  5. Dan Fromm

    Dan Fromm Member

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    The shutter should be a plain ol' Alphax #3, except for the limited diaphragm, nominal speeds 1, 1/2, 1/5, 1/10/, 1/25, 1/50, 1/100, B, T.

    I have no idea why the seller is asking so much. The price is ridiculous. Two thoughts spring to mind. Breguet Camera sells, for the most part, high-end equipment to, for the most part, rich and, perhaps, ignorant collectors. The lens in question is in an adapter, apparently non-focusing, to M-42 so may be aimed at rich and ignorant experimenters who want to try out odd lenses on their tiny chip digital cameras. Look at his sales.
     
  6. djkloss

    djkloss Subscriber

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    thank you Nicholas,

    Fortunately, I'm not looking to buy the lens as I already have one (came with the collection of my dad's). I wonder if I should've kept the oscilliscope that he had. :wink: I was just doing a little research and I knew I could count on my APUG friends for information.
    The lens I have is the same one as the link I posted. Interesting though, that you would have to move the shutter speed indicator to "B" to close it when shooting a time exposure.

    Might be fun to try it out - kinda like a Holga :smile:
     
  7. Dan Fromm

    Dan Fromm Member

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    Wrong. On "T", trip once to open, trip again to close. That's what cable releases are for.
     
  8. djkloss

    djkloss Subscriber

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    I did that. It didn't work.
     
  9. Dan Fromm

    Dan Fromm Member

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    Interesting. Mine works as expected. Yours needs service.

    Cheers,

    Dan
     
  10. shutterfinger

    shutterfinger Subscriber

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    Any shutter make,
    T- set if not a self setting shutter, trip=shutter opens; second press of trip lever should close the shutter or turn the speed dial to another setting to close the shutter. Norm is either or not just one to close.
    B- set the shutter if not a self setting shutter, press trip lever=shutter opens and stays open as long as the trip lever is held in the trip position and closes instantly (shutter's fastest speed) when the trip lever is released.
    Timed settings- set if not a self setting, pressing trip lever causes the shutter to open and close at the selected time. Keeping pressure on the trip lever will result in the speeds being slow or the shutter to stay open until the pressure is released from the trip lever on many makes of shutters.
    Standard speed tolerance is 20% for 1/100 and slower, 30% for speeds 1/125 and faster or roughly 1/3 stop error.
    Shutters not preforming to these guidelines need servicing.
     
  11. Whiteymorange

    Whiteymorange Member

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    I played around with one of these oscilliscope lenses one day with an 8x10 camera and some paper negs. The individual cells on mine resolved an image quite well, with a much longer focal length. Soft, but not as oddly focused as the whole lens together. I have no idea what the design of the lens is, but it seemed symmetrical. Just playing, of course, and no measurements were taken. In the end, I gave the lens back to its original owner. I have too many "sorta' interesting" projects without one more.