[Leica] Filter question on Screwmount Leica

[jhnichols at bellsouth.net (Jim Nichols)]

David,

The outer diameter of my Summitar measures 1 5/8 inches, or 41.7mm.  The 
slip-on adapter that I use is labeled "Kodak Series VI Adapter Ring 1 5/8 
in. - 41mm Made in USA".  I've had it for some time, so can't suggest a 
source, unless you can get to an "old-time" camera shop where these things 
have accumulated over the years.  I use a short retainer ring or a Series VI 
shade to secure the filter in place.  If you can find a vented shade, it 
will present less interference with the viewfinder.  Because I must wear 
glasses, I normally use an external viewfinder, so the shade does not bother 
me.   I hope this helps.  Most of the filter sources cited in other 
responses can supply Series VI filters, often in used but good condition. 
Personally, I prefer the slip-on adapter over the screw-in type because I 
have more than one lens in this diameter, but each has its own unique thread 
size.

Jim Nichols
Tullahoma, TN USA