When I carry my 100-400, particularly if it's tilted down and most especially if it's fully extended, I can hear and feel what I presume to be the IS system rolling and clunking around inside. The lens is sharp and functions properly otherwise, I'm just curious if I should feel that IS motor moving inside while simply walking (I'd understand if I was in a full-out sprint down the road with it).
It's still under warranty and if it's behaving improperly, I suppose I should get it taken care of. Like I said, it performs well otherwise and maybe that's just normal for this lens.
Thanks in advance for any answers or opinions.