Stiff aperture ring in Leitz Elmar f 5=cm 1:3.5 screw mount________Motion Lapse Film 

The aperture ring was very stiff in this Leitz Elmar f 5=cm 1:3.5, but it's "easy" to fix with the right tools.
Just be aware of the very little set screw on the side and specially the hole it sit's in and the side of the lens assembly.
Use small amount of good grease on the inside of the ring and also on the lens assy and the move the ring to spread the grease, here I use "Super-Lube" but you can also use other good grease. Take care when screw in the 2 small screws in the ring, it can be a little tricky.
The lens assy has to sit correct, so, when putting it back into the body, be sure that the set screw can be screw in fully.
There is also a little set screw on the side of the front ring, but it was missing here :-(....