which filter did your friend get to successfully fit and permit the lens hood to be installed? I am currently having that problem. The camera store only had the Promaster UV filter and the outside diameter would not let the hood be installed.
I have that problem and it seems others do as well. The hood supplied by Canon with the lens, physically cannot be put back on when a filter is installed. I was at the camera shop today and they could not figure out how to solve the issue.
