Once the steel bayonet ring was removed the whole coupling mechanism of the auto aperture mechanism could be lifted out. This resulted in the dispersal of a large number of tiny ball bearings. These you donÕt need anymore but try to make sure they donÕt fall into the inside of the lens mount where they could gum up the works. In this slide note the parts that have been removed from the back of the lens and also visible is the steel colored bronze bayonet mount that was salvaged from an EF lens that someone discarded. It was not from a Canon lens but it does not matter. Even a plastic body cam could have been used but since I had this metal ring I went with it. Also, the 135 mm f/2 lens is quite heavy and I felt better with a metal mount. Lacking this surplus one I thing a Canon EF extension tube could have been sacrificed or maybe there are other sources of lens mounts that I canÕt think of right now. A SAFETY NOTE: At this time it may be prudent to place clear adhesive tape over the rear surface of the lens to protect it from accidental damage. The tapeÕs adhesive will not affect the lens coating as far as I could tell. YouÕll see what this looks like on slide number 19. I must admit I did not do it until later in the proces but I think it is a good idea to do it earlier rather than later.