Hopefully this is the right forum for this question and someone will have an answer. I have a vintage (film era) Vivitar 28-70 F3.5-4,8 macro zoom lens which I can't get to zoom properly. The zoom ring will not move outside the 28-40 area no matter what I do. Pressing the macro button doesn't help, it does not appear to do anything. I have tried both on and off the body of my ME Super. The lens is in pretty good nick otherwise and I would like to make use of it. Does anyone have any ideas as to how to free it that won't involve professional help costing 2-3X what the lens is worth. Thanks.