Archived posting to the Leica Users Group, 2005/05/11

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Subject: [Leica] ltm to m adapter
From: jbcollier at (John Collier)
Date: Wed May 11 05:53:40 2005
References: <> <> <004201c555e8$de841960$3201a8c0@AUG01>

The M3 has framelines for 50, 90 and 135. Wider lenses required the use 
of a separate finder or, in the case of some 35s, a lens with finder 
goggles to modify the field of view (still keyed 50 but the goggles 
modified the field of view to that of the 35 mm lens). The M lens mount 
is 1 mm further away from the focal plane than LTM lenses are. This 
allowed the use of LTM lenses on the new M camera by threading a simple 
1 mm thick adaptor to the LTM lens.

The M3 always displayed the 50 mm framelines and added the other 
framelines as their respective lenses were mounted. So the clearest and 
least cluttered viewfinder was when a 50 was mounted. Now, as there was 
no 21 mm lens yet, the adaptors were marked 135 (or 13.5), 90 (or 9) 
and 28-50 (or 2.8-5). With the addition of the M2 and a 21 mm lens, the 
adapters were marked 35-135, 90 and 21-50.

Early wide M mount lenses (including the 35s with no goggles) brought 
up the 50 framelines. With the arrival of the M2, the 35s without 
goggles now brought up the 35/135 (135 only on the M3) framelines but 
the superwides still brought up the 50 framelines. As the M2 took over 
the sales lead from the M3, and all future finders were based on the 
M2's design, super wides were changed to bring up the 35mm field of 
view. With the addition of the 28 framelines to the 90 set, superwides 
were then changed to bring up the 28-90 rather than the 35-135 

So there are there frameline positions: 35-135, 50-75 and 28-90. 
Depending on when a lens was made, if it is wider than 50, it may bring 
up the, starting from the oldest, 50-75, 35-135 and finally 28-90 
framelines on a new camera (note: different mag finders delete one of 
the frameline sets in either the 35-135 or 28-90 pairs).

The adapters are marked to suit the cameras that were manufactured at 
the same time. So the 135 adapter is marked (dropping the cm 
designation for a smattering of clarity) 135 or 35-135; the 90 adaptor 
is marked 90 as the 28 mm framelines didn't arrive until the production 
of adapters had stopped (I think?); and, the 50 adapter was marked 
28-50 or 21-50 as again production had stopped before the 75 mm 
framelines were added (i think?).

God that is way too much about framelines,

John Collier

On 10-May-05, at 11:18 PM, Ruben wrote:

> I found an adapter from LTM to M from Leitz with the marking 2.8-5 cm
> My question:
> Will this adpater change the focusing range - the abillity to focus at 
> infinity etc. ??

In reply to: Message from patrick at (Patrick (Washington, DC)) ([Leica] Nikon D2X review)
Message from daniel.ridings at (Daniel Ridings) ([Leica] Nikon D2X review)
Message from ruben at (Ruben) ([Leica] ltm to m adapter)