Yes Steve just the same 400-640 th of a sec is still slow for handheld action shots you can do a test and look at the exif data with and without to confirm No Circular types are only for Polarising filters or combined UVpolarising filters.   These Filters have glass crystal embedded in a circular pattern to filter out "Dirty Light" which causes blurred edges and blending colours.

Danny O'Byrne  http://www.digitalartzone.co.uk/

"All the technique in the world doesn't compensate for the inability to notice" Eliott Erwitt