I also found a good workaround. I took perhaps an inch and a half long strip of Velcro (loop side not hook) cut to ~3/16" wide and centered it on the smaller diameter ring seat. This was enough to lock down the collar as needed while allowing the c...
I am an experienced photographer with a variety of lenses with collars and I agree with tangogal. My 100-500 collar will not lock down all the way. I did not notice (or care) very much when hand-holding the camera but once on the tripod it became m...