I bought a HOYA UV filter for my L lense saturday. I just got it for insurance on the lense glass but the guy was trying to sell me a polarizing filter too. I didn't get that one but it brings up the question- How many of you use filters? What kind? Do you change them out for different situations or, say, as in my UV filter, leave it on indoors or out? Just wondering, I saw where best buy was offering 3 different lense filters for $15 each, one was a "distortion", another sounded like it was shaded. I just wondered who uses what and why? Thanks-Bran