How to adjust the rangefinder of a Polaroid Land Camera 350?

Discussion in 'Camera Building, Repairs & Modification' started by Chobonaut, Feb 12, 2011.

  1. Chobonaut

    Chobonaut Member

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    Hi there,

    after i modified my Land Camera for modern Batteries (2xAAA, no timer needed) i am in the mood of taking a look at the rangefinder as well - although he is just slightly out of focus and one can still focus properly.

    The problem is - i do not know how to do it! Would be great, if you could help me.

    Thank you!
    Tim
     
  2. BobCrowley

    BobCrowley Subscriber

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    The traditional way to make a small adjustment is to carefully bend the small metal tab where the struts meet the sliding portion of the rangefinder. With no film in the camera and a small piece of ground glass taped into an old film holder, mount the camera on a tripod, and move be bellows to the infinity setting. The object should be in sharp focus when checked with a magnifier. Now check the rangefinder. That should agree. If not, carefully, bend the small tab left or right so that it does agree.

    You can then repeat the same experiment at a close distance, perhaps 10 feet. Carefully check the ground glass. Then the rangefinder. Perfection is impossible, as the rangefinder does not perfectly track focus, but it is very close and certainly good enough.

    If you don't have a ground glass, use frosted tape on a small glass slide or other flat piece of glass taped into the film holder at the exact place where the film would be. You won't get the entire view, but enough to perform the adjustment. Place the tape on the lens side of the glass. An image will form on it.

    Are you sure it is out of focus? Try a tripod and a subject at infinity and if the error is small you might live with it or gently tweak the tab. Notice that you can slide the rangefinder arm all the way to the left (looking at the camera from the front) and that is closest focus. It should spring back without sticking. Try doing that while looking through it and you will see which way to go. It should not be far off, and if it is, look for some other damage, distortion etc to the camera struts.

    Get some Fuji FP100B for it and try that before it is all gone!
     
  3. hpulley

    hpulley Member

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    You sure the FP100B is gone? I just bought 10 packs and the expiry is 2011-11. Admittedly some of my FP3000B packs have expiry of 2012-01 but some of the FP-100C packs I got are expiry 2011-04 so I better get shootin'!
     
  4. BobCrowley

    BobCrowley Subscriber

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    It's not all gone. That's why I recommend getting it while you can! Beautiful stuff, and we might never see it again.
     
  5. matt S

    matt S Member

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    adjusting zeiss finder on polaroids

    Hi Tim,

    If you are talking about the 250-350-450 series with the zeiss finder, and you need to adjust the horizontal and vertical of the rangefinder patch, then there are two screws you need to adjust. Taking the finder off the camera and taking the cover off the finder is not too difficult (if I remember correctly). The vertical screw is a tad trickier to adjust (it is sealed for a reason).

    The screw for horizontal alignment:

    [​IMG]

    and the vertical alignment:

    [​IMG]

    hope this helps some.

    matt
     
  6. Chobonaut

    Chobonaut Member

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    matt S - thank you very very much! You solved my Problem! :smile:
     
  7. homeiss

    homeiss Member

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    Thanks Matt! This also helped me. :D
     
  8. kirkmacatangay

    kirkmacatangay Member

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    Hi Matt,

    For the Polaroid Land Camera 350, the lens focal ength is around 115 mm. If you change the lens out with a 75mm or a 165mm, the rangefinder focusing will not correspond on one end of the range finder.

    Is there a way to modify the swing arm to compensate for a shorter or longer lens? Or is there a more intensive modification or fabrication needed? Based on your picture, a new cam swing arm would likely need to be made. Something for me to think about.

    Kirk