I've read on the-digital-picture.com that you needed a UV filter to complete the weather sealing on some of the L lenses.
16-35 II & 24-70 are ones that I have.
I'm not one that likes using filters but thought of buying some to complete the weather sealing now that I have a 1Dmk3
I decided to call Canon Customer Support and the rep said that those lenses are seal as long as it's on a 1D series and no filter was needed. Of course he was just reading off the discription of the lens.
Can anyone shed some light on this subject? Have you read in any Canon Manual that it says weather sealing is dependant on the filter?