(I posted this in another forum, but thought I would share with my other community here, too, if this is not against the rules.)
I have hardly used this lens since getting it: the brutal ice and snow and wind and cold (and other responsibilities; though mainly the ice and snow and wind and cold) have been discouraging both me and the wildlife.
But this morning was warm, and some critters made a show, so I took an outing. I noticed that the lens was a little wobbly on the tripod, and it looked like the issue was between the collar foot and AS plate. I tightened the hex screw, but to no avail. What was weird was that it was not twisting, but rather wobbled along the front-back axis (i.e. tilted ever so slightly up and down). I could not seem to tighten it down. Worried that I might be stripping something, and not trusting the wobble. I decided to just handhold the lens instead.
Got back and thought I would take off the AS plate to examine it and maybe try to reattach it. Well, that was a lot easier than I thought. At least, the first part was. A few turns in and the whole thing popped off! It looks to me like there is a little sleeve or collar with threads on the inner side on the bottom of the Canon tripod collar foot, and this is what the 3/4" bolt screws in to. I have no idea what used to hold the sleeve/collar in place in the socket. Maybe it was glue or epoxy or wishful thinking of some kind. But, one way or another, in my case, it wore off. [EDIT: On close inspection, it looks like the little sleeve/colllar/thingamajig snapped off. The head is still in its socket in the lens foot, and you can see the jagged edges on the top of the part that is stuck to the 3/4" screw.]
I am open to the possibility that this issue may have been exacerbated by an error on my part, but I doubt it. This lens has been mostly sitting in a dry box since I got it. On the few occasions I have taken it out, I *have* used the plate + foot as a handle ... but surely that does not constitute abuse?
I am looking on the bright side. This scenario could easily have occurred in other circumstances with much worse or sad circumstances (in the long run, more sad for my insurance company than myself, I suppose). As it happens, occurring as it did in this controlled environment, I learned something new and useful about this lens. Do not trust this tripod foot. I have just ordered the Kirk replacement. I might try seeing if this is covered by the Canon warranty, but honestly think this is a design flaw, and the only reason to pursue the warranty is to maintain the resale value by being able to include an intact OEM foot.
