"Sticky" zoom on Canon 100-400mm lens

Started Sep 29, 2012 | Discussions thread
willvan Senior Member • Posts: 2,129
Re: "Sticky" zoom on Canon 100-400mm lens

The fabric/felt used in the ring that controls the tightness seems to be fairly fragile and there have been reports from time to time where the fabric has broken down and fragments actually come out from under the ring. I am going through this now with my 100-400. Initially the push/pull started to jam at specific points and would not fully retract. I suspected that one of the tiny ball bearings inside the mechanism had worked its way our of the race that holds the bearings in place. This problem seemed to clear itself and then I started to notice pieces of the black felt material coming out from under the ring. Now, when the ring is tightened it does not apply enough pressure to stop the lens from zooming out....just the opposite problem that you are having. I am not certain if my problem is related to the ball bearings, the felt or both but it looks like I am faced with sending the lens to Canon and quite possibly a servicing cost somewhere around $350. My lens is just under 5 years old and while I have used it a lot, I am very careful with it. In your case, other than wiping the lens barrel with a damp cloth and then drying it thoroughly, I would not be inclined to use any lubricant as this may cause the felt or whatever is used as a gripping agent to deteriorate. However, I did nothing to mine and it still malfunctioned.

I hope this helps,


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