« on: January 19, 2015, 01:35:44 PM »
I had a version 1 of the 400mm DO and twice on international trips, the front and rear barrel assemblies on the lens became loose, then completely broke apart -- the first time causing the distal 60% of the lens to crash onto the pavement. I had the lens hood on, so the glass was not damaged. Canon charged me $370 for the repair.
These two barrel assemblies are held together by internal bolts that are not accessible to the average user. I have heard other stories from friends of similar behavior with this lens.
I found it completely unacceptable to have a $6,000+ lens break into two separate pieces during normal usage far from anyplace I can get it repaired. Luckily, the second time, the break occurred on the last day of my trip.
No one else ever seems to mention this issue. Hopefully, they have fixed this problem in version II.