I am looking to invest in a CPL filter for the 12-40mm Pro lens (and step up rings for other lenses that I have). I was wondering how often people use polarizers with the 12-40mm Pro lens and whether they have any suggestions on which polarizer to get. Currently, I am looking at the Marumi 62mm CPL Super DHG MC filter as I have heard some good things about this filter. Anyone have any experience with it? If you do have one, is it easy to clean (I have run across some high quality filters that are such a pain to clean). Also, I currently have a clear UV filter on the lens, would I use this polarizer on top of the UV filter or do people typically take off their UV filter and put the polarizer on. Will having both a UV filter and a Polarizer on cause vignetting at the 12mm end?