Konica Pearl III, rangefinder adjustment?

Discussion in 'Medium Format' started by ricklb55, Jun 7, 2017.

  1. Just acquired the Pearl III. U.S. $190 I have not yet put film through it but so far I am not terribly impressed:
    1. The shutter/lense is not quiet parallel to the plane of the film. Is this a significant issue?
    2. The shutter/lense is a tad loose. Not really a problem but it just makes the camera feel cheap.
    3. The rangefinder is not reporting the correct distance. Anybody know how this is adjusted? I removed the plate the contains the film type dial but it only exposes a screw for the vertical alignment of the rangefinder mirror.

    The good: very little wear, very clean lense, all shutter speeds are accurate to the ear, no leaks in the bellows, it has a PC synch and it fires a flash.

    Did I pay too much? Feels like it.
     
  2. 1. Yes, it affects the plane of focus. Check for not fully opened bed/locked bed braces, something may be bent.
    2. With the bed closed open the camera back, tighten the retaining ring around the rear of the lens/shutter, it will have notches 180° apart at 90° intervals.
    3. Once the lens/shutter is tight and the camera opens with the lens parallel to the film plane check the RF again. The linkage may be loose, bent, or a mirror may be loose inside.

    I think you paid too much, return it if possible.
     
  3. 1. Linkages lock and none look bent. There is a very small adjustment screw and it brought the lens a bit more parallel but not by much.
    2. The retaining ring was very loose! Tightened by hand and it now is much better. Thank you!
    3. The rangefinder is still way off, even when I manually move the lens to be parallel.
     
  4. I would use a wide straight edge or square and check that the lens standard is perpendicular to the bed. The fact that the lens mount ring was loose suggest that someone else had it off and could not figure out how to correct it or they assembled something wrong resulting the the adjustment not correcting the error.
    I have not worked on Rangefinder Cameras but have serviced side rangefinders for press cameras and written servicing/calibrating instructions for Super Graphic cameras.
    I have seen diagrams for the rangefinder in other makes of RF cameras. They all work on the same principle.
    The fixed mirror is usually a beamsplitter with 50% light transmission, it is mounted at a 45° angle to the light path of the lens. The view eyepiece is in line with the fixed mirror. The movable mirror or prism is connected via linkage to the focus mechanism. Infinity is when both the fixed and movable mirrors are at the same angle. Some rangefinder cameras may use an array of mirrors to compensate for the offset of the eyepiece. I would start by putting a ground glass on the film rails as film is when making an exposure and check focus at infinity. A temporary ground glass can be made by placing strips of Scotch Magic Transparent Tape next to each other without overlapping onto a piece of glass or clear acrylic plastic (CD holder cover), tape side toward the lens. Check with a loupe. A good infinity target should be at least 5000 feet/1524 meters away, the further the better. If the focus scale is not correct then correct it before any further disassembly of the camera. If the focus is accurate then I would suspect that a mirror has come loose from its housing and needs to be reattached. Carefully clean all optical surfaces while you have it open.
    Standard calibration distances start at infinity, then at 25 feet/7.62 meter, 15 feet/‪4.572‬ meter, 6 feet/‪1.8288‬ meter then go back to infinity and recheck/adjust until all focused distanced from infinity to the lens close focus distance is correct. Dirty/stick/slow to move movements are a PITA to adjust, clean, smooth operating ones are much easier.
     
  5. Unless you're a dedicated Konica collector, you paid far too much for what sounds like a piece of unusable old junk. Send it back for a refund!

    At that price it should at least be in fully working order. The words "ripped" and "off" spring to mind.
     
  6. Checking around the internet I can find nothing specific to adjusting the rangefinder on Konica Pearl's. So I plunged ahead and removed the top plate and found two screws just behind (closer to the film side) the 45° mirror that is just behind the rangefinder opening (not the viewfinder opening). The screw just behind the mirror adjusted the vertical. The screw behind that adjusted the horizontal. Got it all adjusted at about 8 feet and felt very proud of myself, but then discovered the rangefinder did not converge at infinite. Getting that correct made the close focus off. From what I have read on various forums it seems there are at least two adjustment screws: one for close and one for infinite. But what have I adjusted? Close or infinite? And where is the opposite adjustment screw?

    FYI, after I complained to the seller he refunded me 50% of the purchase price. Also, with leaving the camera open and allowing the bellows to relax the lense is coming much closer to parallel.
     
  7. Adjusting the rangefinder won't do any good if the lens isn't aligned properly.

    It's all very well for the rangefinder to look OK through its viewfinder, but the position of the lens may still be a mile off and give out-of-focus results.

    From the collection of faults; it sounds like someone has removed and poorly replaced the lens and shutter assembly. This needs to be accurately aligned with the cam or lever that runs from the lens helicoid to connect with the rangefinder. Until and unless this is accurately positioned, twiddling with the prism or mirror angles is futile.

    You need to place a focussing screen on the film plane and check that infinity focus on the distance scale matches with a sharp image of, say, the moon on the focal plane. And that the focus remains good from left to right and top to bottom of the frame.

    Only after that's done and the rangefinder coupling is checked to be straight and true, should you mess with the prism alignment.
     
  8. I agree 100% with post #7.
    Being I don't know the geographic area you are in I cannot recommend a product for the bellows.
    The bellows are likely vinyl. Treat them with a vinyl restorer other than Armorall.
    Pledge furniture polish in the yellow can will work also.

    Its good you got some money back but its still a pricey camera.
     
  9. Could you give clue how this is done?
     
  10. Actually, it is the alignment you are refering to that I don't have a clue about.
     
  11. A makeshift focussing screen can be made from a glass microscope slide with a strip of 3M "magic" tape stuck carefully to it. Put the tape side towards the lens.

    The finely etched tape surface acts like a ground-glass screen.

    WRT the rangefinder "feeler" positioning: I'm afraid you're on your own there. You need to examine the mechanism carefully to see what went where originally. With luck there'll be some rub marks where the cam or arm rested on a moving surface.
     
  12. I also have a Konica Pearl with focus issues. I’ve followed your advice. When it comes to near and far focus though what I the method in general terms of getting near and far objects in focus. I can set the infinity focus. The near focus appears to be good. The mid focus seems a bit out.
     

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