B + W Kaesemann CP Filter - got one. :)

If you're metering in-camera, don't use EC just because you've attached the filter. Set an EC as you would normally if there's a "special" situation (like snow, or a black cat in close-up) and take it from there. Filter factors are for use when you use an external meter, and so aren't metering through the filter.

What is a Kaesemann? Seriously, I want to know.

'Kaesemann' means that the edges of the CPL are sealed to prevent moisture from getting in between the glass elements.

Thanks guys!

They're expensive, but they kick butt. Like good lenses, they are well worth the investment.

Got B+W CPL's for my lenses and won't use anything else (possibly hoya HFC's and the Cokin system for the 17-40L) I just let a co-worker hold it and compare it to his Tiffen and he was shocked.