| Author | Message | ||
     George Welcher Rating: N/A |
Sadly, you can't get to the aperature blades from the back. You have to go in from the front. Lens construction varies, and my experience has been with a couple of screw mount Pentacon lenses. Is this a screw mount lens, by any chance? At any rate, here is a generalized procedure. First, you will need to unscrew the bezel around the front element, using some sort of friction tool, like a large rubber stopper. Set the lens to infinity first. Document everything you do (digital camera with macro setting is useful here), and take measurements, especially lens base to filter ring at infinity. A set of calipers is best for taking measurements. You should see some screws holding the focus ring to the focus helix. Remove the focus ring. Record the distance from lens base to front edge of the lens element assembly. The lens assembly itself should unscrew from the helix giving you access to the aperature and linkage. You may need to rotate the focusing helix to clear an alingment groove. Record how many turns (using index marks helps). There should be no need to remove any lens elements from the lens assembly. Be sure to clean the linkage to the pin or blade protruding from the mount, as this is often the source of sticky aperatures. Reassemble being sure to reset lens edge to base distances as recorded, otherwise your lens may not focus to infinity, and your distance scale will be off. Good luck! |