[Leica] Lens compatibility on Focomat 1s

[bob geoghegan <bobgeo@dgiinc.com>]

(excuse the cross posting)

A recent post on the Topica Leica list mentioned calibrating the autofocus 
for particular lenses.  I've used Focomat 1s, probably 1Cs, that had 50/2.8 
El-Nikkors where the lens & autofocus seemed to be pretty well matched.  I 
can't vouch for either being perfectly optimized.  Of course the enlarger 
has to be calibrated for the distance from a lens's optical center to its 
mounting thread and also for the easel height.  I've done this for a V35 
following their manual.  I've never seen a 1C or 1A  manual.  Doesn't the 
focus cam have to precisely match the lens's real focal length. i.e. 
something like 51.2mm rather than the marked 50mm?  More to the point, do 
50mm Focotars match the Focomat 1 cam precisely while other lenses 
don't?  Or is there some adjustment I don't know about that would let one 
get good AF from a non-Focotar 50mm enlarging lens on a 1C/1A?

BobG
(wanting some kind of Focomat)