Recommended Pol Circ

I'm about to buy a new Pol Circ - needed because most of my current filters are 62 or 67mm, and the 100-400 L takes 77mm.

Any recommendations? It seems like a lot of the L lenses takes 77mm filters, so I thought it might be an idea to go for good quality.

When looking at my local supplier, there is only about 10% price difference between the following:
- B+W MRC
- B+W MRC E (Käsemann)
- Hoya HMC Super

and the following are about 30% cheaper:
- Hoya HMC
- Soligor Digital High Grade

I tried to read up on the Schneider Optics web site, but I can't say I really understood the difference with the Käsemann filter.

I recommened the Hoya Pro1 Digital Circular Polarizer

Many, many threads on this topic: here is one of those, which includes links to others...
https://photography-on-the.net/forum/showthre​ad.php?t=333619

I am a Hoya Pro 1 CP myself.. its a great CPL

For practical purposes, the Kaesemann CPs are better sealed against moisture, thus against delamination (unlike colour filters, screw-in polarizers are all sandwiches of glass and polarizing film). For practical purposes, I haven't had any non-Kaesemanns delaminate in (mumble) years of using them, even with the cheapest brands. Further, you're probably not very likely to want to pull out a polarizer in wet conditions.

I would, however, go with either the B+W MRC or the Hoya S-HMC over the HMC or Soligor. Over the Hoya HMC because that's got a less-effective multi-coating than the S-HMC; over the Soligor basically because I don't really know all that much about them any more. They used to be on a par with Vivitar back in the '70s, but Vivitar's not on a par with Vivitar of the '70s any more and Soligor's pretty well dropped off the radar here.

Yes, I know that there are other threads discussing filters, but it is also a question of local availability. There can be huge differences in price depending on where in the world you buy things, thereby affecting the buy recommendation.

In this case, the three I primarily think about are within a few percent in price. There is also a slim version of the B+W at almost identical price.

Are there any other differences in quality or IQ between the Käsemann and the non-Käsemann version?

I use the - B+W MRC E (Käsemann) with great results. Got it from www.maxsaver.net so it did not cost a great deal.

Thanks for the advice. I went for the B+W Käsemann filter. Heliopan filters where not in my list, because I don't know of a local supplier of them.