Vivitar Series One 90-180/4.5 K-mount lens

Discussion in '35mm Cameras' started by David Goldstein, Mar 6, 2007.

  1. I received my new Pentax K10D today. The main reason I got it is because I
    have some excellent manual focus lenses that I wanted to use on it. One of
    those is a Vivitar Series One 90-180/4.5 K-mount lens--an extraordinary
    lens. Unfortunately, there is a metal collar that partially surrounds the
    rear element that prevents the lens from mounting on the camera. The other
    K-mount lenses I have mount without difficulty. Has anyone had any
    experience with this problem. If I could get the collar off the lens and
    could grind it down, I believe the lens would fit but I am not sure how to
    do this (it would be too risky to try to do this with collar mounted because
    it is so close to the rear element. Any help would be appreciated. Thanks
    David Goldstein, Mar 6, 2007
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  2. David Goldstein

    JD Guest

    Before doing radical surgery that would minimally damage the resale
    value and worse, damage the lens, ask yourself what is the main use of
    this lens? It's a flat field variable focal length macro lens. Do you
    use this lens at infinite focus a lot? I've found that it is prone to
    flare (Olympus OM mount) and don't use it a lot as a short telephoto.
    I use it for macro work. I'd put a short extension tube on it and see
    if it works for your needs. That would eliminate the ability for
    infinity focus though.

    I did have to do minor surgery on my lens, one of the mounting screws is
    positioned in a way that can damage an OM4 mount reset button, so I
    filled in that one point with epoxy. But that's about as far as I would
    go for "surgery" on this lens.

    One thing about the lens, it does give the biceps a workout!

    JD, Mar 6, 2007
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  3. Thank you, thank you. Your solution was so elegantly simple that I am
    kicking myself for not thinking of it. My main if not sole use of the lens
    is for macro work so the loss of the ability to focus to infinity is a small
    price to pay. I have a set of extension tubes and your suggestion worked
    like a charm even with the shortest tube

    David Goldstein
    David Goldstein, Mar 6, 2007
  4. David Goldstein

    JD Guest

    Glad it works for you. I forgot to mention that whenever you put an
    extension on a zoom, you lose the constant focus capability. But that
    just makes this Vivitar like a Vivitar 28-90 - a varifocal lens. Now go
    shoot some bugs.

    JD, Mar 7, 2007
  5. David Goldstein


    Mar 14, 2007
    Likes Received:
    go ahead shave it down

    I also own the 90-180 Macro zoom. You just have to take off the 4 little screws in the SIDE of the mount. That will allow you to take the baffle off. Grind to your hearts content and re-install (if you haven't lost any of the teeny tiny screws.)
    Very painless and AFAIK would increase value to all Pentax users....
    jeffkrol, Mar 14, 2007
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