[Leica] Late & Early 50/2 DR on M6

[Stephen <cameras@jetlink.net>]

I was curious about the different versions of 50/2 DR on the M6, so I
borrowed a late one and compared them on a late M6.

The early version is marked in either meters or feet, but not both.
They are also marked in their repro ratios from 1:15 to 1:.75.    The
"eyes" for these have the "condenser" trademark, inside of which is "E.
Leitz Wetzlar."

The later version after is marked in both feet and meters, does not have
the repro ratios, and focuses to 20".    The "eyes" for these are simply
marked "Leitz Wetzlar" without the condenser trademark.

Comparing an early version # 1404739 with a late version # 2107862, side
by side, there are only very small differences.

    The second version has wider and deeper knurling for the focusing
grip.

    The focusing mounts and barrels appear to be identical.

    The lens heads design and glass appear to be identical, at least
from the outside.

    The second version lens elements seem to be mounted within an
Aluminum mounting,                    as  opposed to the earlier brass
mounting.

    The second version has a "warmer" lens coating

Keep in mind these differences ONLY represent these two lenses, other
changes might have come and gone with the len's production life.

Now we come to the mystery problems of using these lenses on the M6.

NEITHER lens would mount directly on my late M6 # 2184470 if the lens
was focused at it's closest normal focus, i.e. 3'4."    However, mount
the lenses focused at infinity, and they both mount perfectly.    BTW,
this seems to be a problem of the M6 (or at least the late ones) since
there is no such problem on the M4 and M3 I tested.

The situation was duplicated if I tried to remove the lens when focused
at 3'4".   Yet, by turning the lens to infinity, it removed beautifully.

Both lenses would also dis-mount perfectly if they were focused at the
starting point of the near focus zone.

SO, at least for the sample lenses in question, both versions will work
fine on a late M6, just so long as you remember to mount and dismount
the lens when it's focused at infinity.   Not sure yet if this would
hold true with an early M6.

Regards,

Stephen Gandy