Hi,
there is also an additional option, which works remarkably well,
but is a bit expensive or required some work.
I think Leica did produce a swinging polariser mount, which was
attached to filter threads and allowed you to swing the polariser
either in fron of lens or in front of viewfinder, in such a way,
that the filter was always same aligned.
While finding that item from Letiz might be difficult and certainly
expensive, my friend when departing to Peru had a local competent
machinist make him a similar, improved one, for quite less money.
It worked like a charm, with all of his Bessa lenses, even the 15mm
if I recall correctly. So if you are competent in this field or
know somebody who is, you might investigate that.
Good light!
fra
