Repairing a Carl Zeiss Jena Sonnar 3.5/135mm Lens

The Carl Zeiss Jena Sonnar 135mm f/3.5 lens is a compact tele lens, made of 4 elements in 3 groups. It is famous for being rather sharp, with a minimum focus distance of only 1m. This version was made in the 1970's and features multi-coating.

When I got this, the focus was somehow stiff and there were traces of oil on the aperture blades, so I decided to clean it. Here, I document the individual steps in pictures.

For the first steps, no tools are required. Everything can be unscrewed by hand.

These are the pieces so far. Now, we need a screwdriver to take off the back piece.

Removing the two helicoid keys and (of course!) take a precise note where they came off!!!

Removing the screw that sets the limits for the focus ring.

Remember where you started (I started at minimum distance of 1m).

And count the number of turns before the helicoid comes off.

For the coarse helicoid, note exactly the point where it comes off (it has multiple entry points!)

Clean and relube the helicoids.

And reassemble eeverything.

I don't have pictures of the remaining steps. But at this point, you just have to undo what you did in the first steps.

More of my lens repair tutorials can be found here.