My EF 28-70mm f/3.5-4.5II broke after about 9 years (bought in 1990) of use. It seemed like some internal gears stripped, so it would not focus to infinity, the manual focus was very rough and both focus and zoom would sometimes stick (maybe broken parts jamming up the mechanism and I heard a screw loose inside). It was returned to Canon Canada (in Calgary AB) who fixed for a fee as it was no longer under warranty and returned it to me in about 4 weeks. It worked fine for awhile, but in August 2000, only the zoom component broke (i.e.: the zooming lens would not squarely slide up and down in the lens barrel) and the movement was rough. I had it repaired again around March 2001 and just recently it has broke again (September 2001). Does anyone have an idea what is causing this problem? A repairman I took it to thought it was because of the filter I had screwed on, but I have not been using the filter now. Is it because of the plastic used in the version II of this lens, apparently the original lens had more metal components. Is it worth repairing this lens or should I buy the 28-70 2.8L assuming it is built to last. IMO my lens has an inherent design flaw or the use of inferior materials including the replacement ones.