Archived posting to the Leica Users Group, 2000/05/14
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]The three screws are almost exactly as you described. The third screw with the eccentric behind the rangefinder's arm limits the "inward" travel of the rangefinder arm and the thin "flap" off the rangefinder pivot that contacts this same third adjustment limits the "outward" travel. So we can limit the rangefinder's movement, not something that we need lose sleep over, and we can also adjust the roller's vertical position by bending the arm. These adjustments are factory set and only need readjusting after catastrophic events such as we have nightmares about. Let us disregard them. The roller is indeed on a eccentric screw and it does the fine adjustment of the rangefinder's arm rotational position. The rangefinder arm is attached to the rangefinder mechanism at the pivot end by yet another eccentric. This one has a lock screw and the eccentric is adjusted by moving the slotted tab. This adjusts the range of rotation a given lens cam movement will impart by changing the length of the arm. A shorter arm gives more rotation and a longer arm gives less rotation. One checks the rangefinder at infinity, at 10 meters and at 1 meter. One has to adjust the length of the arm so that when the roller eccentric adjustment is done to give correct indication at infinity, the other two are correct as well. It is a Zen thing. The factory and distributors do not use lenses to do this but a special jig with a mount for the camera and a target with all the various marks so you can do the above adjustments and more. The rangefinder arm is worked with a special tool that mounts on the lens bayonets and has stops for each of the three measuring points. Cool. The more I learn about this the more inclined I am to leave it alone ;-). One could easily rig up targets at fixed distances but one would have to use a ground glass to compare focus between the rangefinder and the film plane. I hope this has helped to clear things up somewhat. After a good solid whack, it is not unusual for the infinity indication to be off. Commonly people then reset the roller position to correct things. I do not know what actually gets shifted but it is reasonable to assume that range of rotational movement does not need to be changed, so we do not have to adjust the length of the arm, but that the infinity just needs to be reset by adjusting the roller. A very long winded reply to say: Yes, tweak the roller eccentric for minor in service adjustments. John Collier > From: Rick Dykstra <rdandcb@cybermac.com.au> Dig it up yourselves. If I quoted the thing this message would be ridiculous in length! :-)