What happens next is VERY difficult to explain but that finger needs to be glued to the aperture setting ring ... somehow. I think I did this as a two step process. First I added (glued) a small metal piece to the plastic ring. This part was so small as to not interfere with the travel excursion of the ring as it moved from f/2 to f/32. Once this was done I glued the finger to that metal piece and to the plastic where it was exposed. This was done while the lens was focused at infinity (meaning that it was as collapsed as possible) and the finger installed in the bronze fork rising from the lens body cavity. The aperture ring needs to be set at f/2 and the lens aperture mechanism also needs to be at f/2. Holding this mechanism consisting of a pin and a cam in place is somewhat of a precarious situation. The pin tends to slide down the cam and the aperture is set to something other than what the aperture ring is set to. It is another procedure where 1st hand experience is the best teacher. In any case doing this properly allows the aperture ring to accurately (more or less) set the lens aperture regardless of what distance the lens is focused on.