Polarizer: Käsemann or Slim?

[cici]

I need a polarizer and prefer a circular polarizer.

The problem is, that here in Europe I have only the choice between:

- Käsemann from B+W or Heliopan
- Slim from B+W or Heliopan


Käsemann: is supposed to protect from dirt and dust between the layers, but might vignet...

Slim versions should NOT vignet, but lose in quality with each particle (e.g. dust) that enters during all the years of use...

I can't find a Käsemann Slim Circular Polarizer from neither B+W nor Heliopan.

What would you choose and why?

I have to say that I would use the camera in "normal" condition - rarely in dusty environements that would clearly require the Käsemann version...

 

[THoff]

I'd go for the Käsemann because you don't need a slim CP -- a non-slim CP won't vignette, at least mine doesn't.