1. Remove lens block
First, remove the locking screw (right). Only then can the lens block be unscrewed.
The black rear lens block can be unscrewed relatively easily, e.g., with the help of a rubber glove.
2. Remove the aperture ring
Remove the 3 small grub screws that hold the aperture scale in place.
The two grub screws that hold the front ring in place can only be accessed by unscrewing this ring and then removing the aperture ring housing.
Mark the position where the grub screw was and count how many turns it took to remove the ring. This is exactly how far it must be screwed back on again.
To finally remove the aperture ring, this screw must be removed (left). It can then simply be pulled down.
3. Old and new grease
Remove the old sticky lubricant and apply new lubricant.
4. Remove front ring
Now we need to remove these grub screws (there are two opposite each other) in order to unscrew the front ring with the serial number.
Then the mounted front lens can be removed. The front lens even has a serial number, which is the last five digits of the lens serial number.
Now clean all lenses with alcohol or lens cleaner and reassemble the lens.
