Changing Lens On Perkeo 2

Discussion in 'Medium Format Cameras and Accessories' started by Lyrrad, Jul 23, 2005.

  1. Lyrrad

    Lyrrad Member

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    Hi

    Can anyone tell me if it is a simple job to replace a lens (like for like) on a Perkeo 2. I have a donor lens marked in feet that also seems to be brighter and cleaner than the metric one I have on my camera. If anyone knows how to do this then feedback would be appriciated.
     
  2. David H. Bebbington

    David H. Bebbington Inactive

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    I do not know this camera but have just looked it up and see that it does not have a coupled rangefinder or other complications. Replacing the lens should be as simple as unscrewing the retaining ring of the old lens (do it with the bellows closed and use a tool such as circlip pliers or a lens key for a 00 size shutter if you can find one) and screwing the ring back onto the "new" lens.
     
  3. Ole

    Ole Moderator Staff Member Moderator

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    Just remember to check the focus with a piece og ground glass after changing the lens. You should do this anyway, it's amazing how many of the really nice cameras are practically unused since they've never been sharp. Shimming the lens mount can make a lot of difference!
     
  4. Lyrrad

    Lyrrad Member

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    Ole

    Sorry for my ignorance, but as I have managed to swap the lenses around very easily, could I please ask you to explain to me step by step how I would check the focus with a piece of ground glass. Also where can I get a piece of ground glass (does it need to be a particular shape/size/thickness).

    Many thanks in advance.
     
  5. Ole

    Ole Moderator Staff Member Moderator

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    You need a piece of ... something. Which fits across the film rails, which are the shiny things above and below the opening when you see the camera from behind with the back open. You can use a piece of film, even - I've done that. Surely everybody has a piece of film that is sadly grey and featureless?

    Put your GG substitute across the film rails, open the lens (on "B"), set lens to infinity. Pointcamera towards something very distant. Does it look sharp? Anyway, twiddle the focus a little. Is there a sharper setting? If so, your infinity is off.

    I did one where I cleaned the front group of a lens, and had entered it in the wrong place on the helicoid...

    I changed the lens on another camera, and needed to take off about 0.5mm from the lens mount to get a good infinity focus...

    Thickness is not important at all, but the "focus surface" has to be towards the lens!
     
  6. Lyrrad

    Lyrrad Member

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    Thank you