does anyone use ND or polarising filters on their camera? i'm only willing to buy one at the moment (boxing day online sales!) and am leaning towards an ND filter (not sure which - there seems to be a few sorts) so my skies aren't always blown out for the sake of landscape and people, i've been pulling them back a bit with gradient filters in post in Photoshop when I really want. Any opinions or advice happily accepted!