Re: SM-to-M Adaptors/Leslie

[Leikon35@aol.com]

         Leslie - No, it is not a stupid question; it has been asked many
         times.  In developing the M3, Leitz realized that many of the
         owners of the new cameras would want to use some of their old
         LTM lens on the M3 body, so they made the body flange 1mm
         thinner to allow for the thickness of the adapter. Actually they
         made 3 different rings, with different cams; 50,90 &135. There 
         was no need for the 28, 35, & 75 as the M2, M4,M5 & M6 did
         not exist yet.  When the M2 came out, the rings were marked
         35 M2 & 135 M3 - the 90 was used only on the 90 to the 28mm
         windows apppeared years later. The rings only purpose is to
         allow the use of LTM lenses on the "M" & all three (there are 
         only 3 regardless of the markings)  have different cams to bring
         up the 3 pairs of windows on the M6 or the 3 individual ones on
         the earlier "M"s.

         Marvin
==================================================         
 In a message dated 97-10-18 06:21:00 EDT, you write:
<< 
 >      Leslie - You have to think about this for a few minutes and then
 >      you will suddenly realize that while the 28-50 ring will take the
 >      LTM 28mm - the ring is actually for the 50mm and will bring up
 >      the 50 & 75 frames on your M6.  You need the ring that has only
 >      90mm engraved on it, it brings up the 90 & 28 together.
 >      If you are not able to find a 90 ring, I have an extra one.
 > 
 >      Marvin Moss
 
 Thank you very much again, Marvin.  I have a question again:
 
 What happens if I use a LTM 28mm with a "50mm adapter ring"
 on M6?  (I know it'll bring up the 50/75 frames, but will
 every other things be ok, like focusing?)
 Does the purpose of a SM-to-M ring includes something
 other than (1) adding some distance to flange back and (2)
 bringing up a correct frames?
 I guess so.  To couple lens focusing to the rangefinder,
 some different focal lengths may require different rings, 
 and therefore there are more than three types of adapter rings.
 Or, there are more than three types because they are some for
 M3, some for later M2, and some for the M6?
 
 Sorry, if this is a stupid question.
 /Leslie