Moskva-5 RF Adjustment...How far away is infinity?

Discussion in 'Medium Format Cameras and Accessories' started by gmikol, Mar 9, 2009.

  1. gmikol

    gmikol Member
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    Hi all...first post on the board.

    I've got a Moskva-5 that's in need of a rangefinder adjustment. I understand that I'm supposed to set the lens at infinity to check for focus with a ground glass on the film gate, and then fiddle with the prism dial to get the RF viewfinder image to line up.

    But my question is this...how far away does infinity have to be? The last marking on the dial is 15m, and there's a lot of stuff between 15m and the edge of the universe. I have a big power transmission line tower about 250m away, but no other really distinct vertical structures any farther, until we go out to the (fairly hazy / cloudy this time of year) horizon.

    Is 250m far enough to calibrate "Infinity" focus? Do I run the risk of throwing off near-field focus if I don't use a target far enough away? Please don't say "Just try it and see", I'm of the opinion that the more times I disassemble something the more likely I am to mess it up.

    Any help is appreciated...

    --Greg
     
  2. Christopher Walrath

    Christopher Walrath Member

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    If your lens is normal to wide, I would think 250m would be sufficient.
     
  3. CuS

    CuS Member

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    1.5m is easier

    I find it easier to adjust the RF on a Moskva-5 to 1.5 meters. I can measure 1.5 meters more easily tan infinity. Call me scalar challenged. :smile:
     
  4. elekm

    elekm Member

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    Adjust your rangefinder for infinity. 250 meters is sufficient.

    When it comes to a camera lens and rangefinder system, infinity is a fixed point, and lens and rangefineders can focus in front of or beyond that by a minute amount, which would then cause other distances to be off.
     
  5. CuS

    CuS Member

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    Very good point - well taken - think I'm gonna be readjusting my Moskvas.
     
  6. pschauss

    pschauss Member

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    I usually use the moon to set infinity.
     
  7. OP
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    gmikol

    gmikol Member
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    Ahhhh...of course...the moon. It's full tonight or tomorrow. Now I need to figure out where I can see the moon from while indoors so I don't have to fiddle with those little screws outside.

    I think 240,000 miles is a close enough approximation of infinity.

    --Greg
     
  8. FM2N

    FM2N Member

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    Hello,
    I have a Moscow 5 and the focus used to be great but I knocked it and now it is off. Where do i start to adjust it? Is there a web site that gives the steps needed? Can any of you lead me through it?
    thanks
    Arthur
     
  9. Samuel Hotton

    Samuel Hotton Member
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    Infinity used to be calculated as 1000 times the focal length. 1000 x 105mm = 105,000 mm 105,000 divided by 25.4mm = 4133.8 inches 4133.8 inches divided by 36 = 114.8 yards.
    Anything beyond 115 yards is infinity with a 105mm lens.
    Sam H.
     
  10. sanking

    sanking Member

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    That is odd. I just took out both a Moscow 4 and a Moscow 5, both with good working rangefinders, and no matter what I did I could only see one Moon through the rangefinder aperture?

    Sandy King


     
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