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.

Repairing a Voigtländer Color-Ultron 1.8/50mm lens

The Voigtländer Color-Ultron 1.8/50mm was built in Singapore from 1974-1977. The original Ultron (with the legendary concave front element) was designed by Dr. Albrecht Tronnier while Voigtländer belonged to Carl Zeiss. When Voigtländer was acquired by Rollei, they commissioned Zeiss to design a less expensive lens to be manufactured in the Rollei factory in Singapore. This lens was sold as the Rollei HFT Planar and also as Voigtländer Color-Ultron. It has 6 elements in 5 groups. It has multi coating and a 6-blades aperture. This is the M42 version - there is also a version for the QBM mount. It is one of the sharper 50mm lenses in my collection and I love its color rendering.

This page has a very detailed description of the development of this lens (use Google translate).

I got mine with a small scratch on the front glass (which does not affect picture quality), but otherwise in good condition. The focusing was a little stiff, and over a few months, the aperture stopped working. So, it was time for a CLA. There is very little information out there on repairing this lens, so maybe the following pictures will be helpful.

Today, I'm too lazy to write much text, so I'm only posting the pictures of the disassembly.

Now from the back side.

Careful: Don't lose the little ball for the aperture click.

From here, you go backwards. I would recommend, first, to assemble all of the front side. The assembly of the back side is some pain. In one step, you have to ensure that three elements fit together - at the same time: The connection for the aperture ring, the helicoid key and the connection for the aperture stop-down pin - while simultaneously making sure that the ring (front left in the 15th picture) is correctly centered. This took me forever. So, I would conclude that this is not the easiest lens to work on.

But now the aperture is working again, and the focus is super smooth. It will be fun to use this great little lens again!

More of my lens repair tutorials can be found here.