I am looking for a circular polarizer for my 17-40. I only found one Hoya 77mm from B&H - if I choose Hoya, it will be easy. http://www.bhphotovideo.com/c/product/391185-REG/Hoya_XD77CRPL_77mm_Circular_Polarizing_Pro.html I have B+W 77mm MRC UV filters and never noticed any distortion so prefer to stick with B+W. Search for "B+W 77mm MRC" yielded 3 results. What is the difference between these three? The extra wide one is $260 while slim is $174 (in middle). Below are the three MRC ones ... http://www.bhphotovideo.com/bnh/con...arch=yes&O=productlist.jsp&A=search&Q=*&bhs=t What do you recommend/use?