Quote Originally Posted by ahab1372 View Post
F-Pro vs F-Pro is just the thickness of the filter ring, both should ( or could be) available in MRC Nano. Using X-pro filters allows for more stacked filters (for example if I'm too lazy to take of the clear filter before I add a ND or CPL, or if I want to combine CPL and ND). If you think it is unlikely that you stack certain types of filters, or if the lens is not prone to additional vignetting with stacked filters, you might as well choose the F-Pro version. Might be slightly easier to handle as well.
A quick check on B&H for a 82mm filter the MRC Nano was only available on the XS-Pro. The $79 filter Brant mentioned had only the MRC coating.
Possibly they would be available somewhere else.