[Leica] 60mm filter for the 100mm APO Macro Elmarit-R

["Anderson, Ferrel" <AndersonF@ria.army.mil>]

The 60mm filter size is frustrating, but I have acquired leica filters and
use them on all of my trusty, always ready, universal camera outfit lenses,
which include the 24, 60, 100 APO and 180 f3.4 APO telyt lenses.   The
circular Polarizer filter vignettes on the 24, but the newer polarizer is
shorter, and I suspect will not result in vignetting.  I was not aware of
the change, but the older Polarizer has a different serial number than the
newer one, and is visually different.   I have also purchased a step-down
ring so that I can use my serie VIII filters on my 60 mm filter sized
lenses.   Why does Leica use odd filter sizes?  I suspect that they have
adopted this practice to support their filter side of the business.