I have a Sigma 50mm EX lens and am looking at an 18-35mm ART lens. I also put high quality protective clear filters on all my lenses. They will be affixed to a Canon 6D.
I am planning a trip to Colorado, and enjoy shooting on days with poor weather. I know that the Canon L lenses are built to be pretty well sealed, but I was wondering how water/dust resistant the Sigma lenses are when fitted with clear filters?