I appreciate the input thus far. I am "considering" a lens that has a scratch on the glass. I am still learning before I start investing $1500 - $2000 in "L" lenses. This is a 28-135 IS for a couple of hundred instead of $400. I know when one takes a picture through a windshield or screen the focal is beyond and does not show in the final picture. I want to know what effect the scratch will have? Thanks