If you're asking whether it's compulsory or not, No.

For me, it's more for protection, and secondly, it works great to reduce sun flare when shooting outdoors.

You can think of it this way. A cheap filter costs like RM80, if it's got scratched, you can spend a little extra money to buy one.

If your RM2k lens itself get scratched, chances are, it may be not repairable, and there goes your luxury lens becoming a broken paperweight.

This post has been edited by geekster129: Oct 19 2010, 12:26 PM