I was sitting on my office chair, holding the 200-500mm/f5.6 AF-S VR by its tripod collar. This is exactly the reason I don't like these removable tripod collars. That collar was slightly loose and somehow it was aligned such that the lens barrel fell off from it. Hitting the ground straight down from 2.5 feet or so. I have one of those flat, transparent hard plastic sheet on the floor for office chair with wheels to roll on. Initially I didn't see any damage and the lens seems to work fine. Image sharpness remains ok. A week later I finally noticed a crack on the barrel, near the front of the lens. Nikon USA's web site shows a $300+ repair estimate. That lens is now on its way to Nikon in Los Angeles. I sure am glad that the collar on the new 500mm/f5.6 PF lens is not entirely removable. Only the tripod foot is removable, similar to the collar on the 70-200mm/f2.8 AF-S VR.