How to Mount M Lens

P

Peter

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This may sound strange to seasoned M lens users. I noticed some wear on my PII's focusing helicoid. Could it be my habit of mounting the lens on my R2 with the lens at infinity? Should I mount the lens with focusing ring set at 0.7m instead? :confused:
 
Peter this doesn't sound right. I've never bothered about where my lenses are on the distance scale when I mount them but I think they are mostly at infinity. There shouldn't be wear - can you post a pic of the wear?
 
That will be quite difficult as my digital camera is not with me at the moment. I am quite shocked to find wear spot on my PII and Ultron when I took them out for cleaning.
 
On the older lenses with locking infinity tabs, the lenses are usualy locked at infinity when mounting/unmounting them. On the other hand, I've got a Russian camera that I find easier to mount lenses onto when the lens is close-focussed so that the lenses RF cam ring does not push so much on the RF coupling thingy in the camera.
 
Peter said:
I am quite shocked to find wear spot on my PII and Ultron when I took them out for cleaning.
Click to expand...
I don't blame you. The Ultron too? Maybe they are made of "soft" metal? :(
 
I think where the distance is set is a carry-over from the Leica LTM days. On the M series, it doesn't make a mite's difference. Nor does it on any SLR.

I have several Russian "copy" cameras, and I, too, find it helps to move the lens to the closest distance on the Zorki bodies. However, the reason for the infinity catch on the old screw-mount lenses is supposed to have been to make UN-screwing the lens easier.

If you watch the lens closely, to no surprise, the RF flange in the back of the lens moves out forward as it's turned closer, while at infinithy, it's clear back in the way of the cam in the body. Thus it's easier to MOUNT the lens when set at closer distance.
 
On the Contax and Nikon S-Mount, you have to set both the camera and lens to infinity before mounting the lens. On M and LTM, I usually set Telephoto's that have the coupling arm to closest focus to avoid the RF cam riding up and down the arm as you mount the lens. This is true of my 13.5cm and 10.5cm lenses. On lenses with infinity lock, it is just easier to screw them in with the lens locked in position. You don't have to push as hard against the RF coupling with the lens at nearest focus, but you have to be really tired to notice? Other than that, I can't think of any reason.
 
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