just for reference I found
this elsewhere, so basically remove the three screws and unscrew front half from rear CAREFULLY and mark both halves at the point they disengage so when assembling the triple thread aligns properly for focus markers. I wonder if deliberate misalignment can help with getting infinity focus on its own? I've got a nice 70-220 m42 lens too, might have to make this a refurb project and give both lenses a clean (degrease and relube, optics with my scope optics cleaner and blow out the dust). the 500mm looks optically good some loose dust inside, the 220 has more, still, would be good to get to use them on nikon with a non-optical adapter or more likely the Tiny1 when it arrives. Dont really need them, have better nikon lenses but I like these lenses and dont want them to go to waste. Would be simpler to save for a second hand canon I know.