50mm DR Summicron on my M7's

[RichardB]

My 50mm DR serial #1961xxx will mount and focus on my M7 serial #288xxxx and will mount but the focus will not move on my M7 serial # 278xxxx.
Any suggestions on why the difference and what to do to have the DR focus on my other M7?
I looked at the cameras with the lens off and can't see a single difference. I understand the the DR can be problem with certain cameras but I had not heard of what I am experiencing before. Thanks for any replies-Dick

 

[HuubL]

I assume you know that the DR has two focus ranges. If the lens is set in the short range and the "glasses" are off, it won't turn the focus ring.

 

[RichardB]

Thanks, lens is set for normal focus range. I have had this lens since I acquired it with a one owner M3 many years ago. It worked on my first M7 but as I Posted, won't move when mounted on my second M7?-Dick

 

[lewis44]

It's probably the close focus cam hitting on something in the M7. The same thing happens on the Zeiss Ikon and the M8. If you want to use it on both the cam will have to be modified, but then you will not have close focusing. I think there is a thread here explaining it.

 

[RichardB]

For academic purposes, the question really is, why does it work on one M7 and not the other? There must be a slight interference on one M7 and not on the other. Thanks for the replies.
The search function did not really come up with anything and is very hard to use with the charachter recognition.-Dick

 

[lewis44]

You should be able to see a difference if you put the old M7 and the newer one side by side. Looking into the camera the spot where it hits should be to the left in the upper portion. At least that's where the Dr hit on the ZI I had. It may even leave a slight mark. There were some differences, but the why is a mystery. I think there were issues with the M6 as well.

 

[waileong]

Mount the lens at infinity.

 

[RichardB]

No marks, no nothing, looking with light and magnification.
DR always mounted at infinity.
?-Dick