B+W "PL" filter : worth something?

Hi all,

I acquired a set of B+W contrast filters in 40.5mm diameter, to fit my Jupiters.

What I mistook for a UV filter is in fact a "PL3, not a polarizer, but what looks like an "effect" filter, with a closeup lens on the periphery, and a "neutral" zone in the center.

I think this will become an aperture ring extension for my Jupiter 12, by removing the glass.

Am I missing something on this filter's value that would make this a dumb thing?

Sounds like it's a "Center-Spot" filter with the center in focus and the edges blurred. Pretty common with most filter brands. Some, like this Hoya, have no glass in the middle, other, just clear glass. Is this what it looks like???

Yes, this is it. I've been unable to find a reference yet, but your post confirms what I thought.

Since I've quit "effect" filters many years ago (used them too much anyway, but I was young ) I think I'll go on removing the glass (so I'll never know how using this on a Leica turns...)

OK, so I destroyed the filter, which improved its value

I marred the threads a bit, but filters still screw in nicely, so my Jupiter 12 is improved!