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Projection lens adaptation: Luxtar Anastigmat 50mm

Discussion in 'Adapted Lenses' started by gnarlydog australia, Feb 9, 2016.

  1. gnarlydog australia

    gnarlydog australia Mu-43 Top Veteran

    977
    Feb 23, 2015
    Brisbane, Australia
    Damiano Visocnik
    I have purchased a projection lens: Luxtar Anastigmat 50mm made by Kodak, that was designed for a Viewlex projector

    $_57.JPG

    $_57 (1).JPG

    The rear diameter is 33mm and I might be able to squeeze it into a body of a broken Jupiter-8 lens.
    My question: does anybody know what is the focal distance from the rear element so I can see if this lens will actually fit?
    Also, the Jupiter-8 has an iris that I could use as aperture on this lens?
    Can that be actually done or does the iris need to sit in between the lens elements to work?

    From the questions I am asking you probably figured out that I have not adapted any projection lenses before, but after seeing great images taken with similar lenses I am very keen to embark onto a new world of adapted lenses.
    I am happy to fabricate adapters from rings and tubes or get a helicoid to be able to focus the lens if the Jupiter-8 (or Industar 50-2) body won't work.
    Is anybody on this Forum a projection lens adapter? any tips?
    Thank you
    Damiano
     
    Last edited: Feb 12, 2016
  2. barry13

    barry13 Super Moderator; Photon Wrangler

    Mar 7, 2014
    Southern California
    Barry
    Hi, the Pentax Auto 110 system had the aperture in the body behind all the lenses. I've read this can cause more aberrations but it is workable.

    I would think you could measure the flange focal distance with a piece of paper, focus to infinity, point the lens at the sun (don't look!), and raise or lower the lens until the sun is sharp on the paper. Then measure.

    Barry
     
  3. gnarlydog australia

    gnarlydog australia Mu-43 Top Veteran

    977
    Feb 23, 2015
    Brisbane, Australia
    Damiano Visocnik
    Barry, thank you for the suggestion for finding the focal point, and so simple; in absence of sun I might use a poweful desk lamp...
    Re aperture: get to think of it I believe there might be several old cameras that adopted that system of having the iris behind the lens.
    So, the lens I purchased could be actually usable more than just freelensing :)
    Thank you for the tips.
    Now I just have to wait for the lens to arrive
     
  4. Turbofrog

    Turbofrog Mu-43 Hall of Famer

    Mar 21, 2014
    The reason the sun is useful is because you can know for sure that the lens is at infinity. Though it's kind of a moot point with this lens, since it doesn't have a focusing helicoid, does it?
     
  5. gnarlydog australia

    gnarlydog australia Mu-43 Top Veteran

    977
    Feb 23, 2015
    Brisbane, Australia
    Damiano Visocnik
    No focusing helicoid comes with this lens but I am willing to get one to make it work.
    I want to know what the focal point is roughly at infinity so I can buy the correct length helicoid. Since I have seen helicoids offered in different lengths I am hoping to get one that will give me the most throw and be closest to infinity for this les when retracted (shortest setting)
    Also, if this lens focuses somewhere near to what the body of an old Russian lens (glass is toast) offers, I might be even able to use the iris of that lens to get aperture.
    So much tinkering, so little time :hmmm: