Like the rookie that I am I recently purchased a lens that is apparently a pre-1997 model. It is a push-pull version and therefore does not have a tripod collar. I will be using this with my D2H primarily on day hikes and for candids of family and friends. Should I be concerned with the lack of a tripod collar...and if so...can an OEM brand collar be added. The lens is in excellent shape and the glass is flawless. Your thoughts and counsel will be greatly appreciated!