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.

Photo Collages in David Hockney's style

Last fall, I talked with my brother about David Hockney's photo collages and how (a long, long time ago) we had experimented with this technique using prints shot on 35mm film. And we decided to try this again with our digital setups. For a collage of 15-25 photos, you need a limited angular for the individual images. So, I used my beautiful 100mm f/2.8 Meyer-Optik Görlitz Orestor lens, and went out on a cloudy fall day through Downtown Ruston, LA, a few hours after it had stopped raining. For these, I turned off raw capture, and decided only to use the out-of-camera jpgs (although with minimal post-processing of the assembled collages). At least some of these were shot with the Orestor lens at open aperture, to use its vignetting as a creative element.

Initially, I was not that happy with the results - but half a year later, with a fresh view, I consider them worth posting. It's probably not a method/topic that I plan to pursue in the future. But maybe, occasionally, it could be something to try out.

More of my photography is posted here.

Repairing a Schneider Curtagon 35mm f/4 Lens

The Schneider Curtagon 35mm f/4 seems to be a pretty rare lens. Web searches don't come up with much (any?) information. Everything I was able to find was only about other versions, a "PA" version (tilt-shift) or Retina versions (silver, with DKL mount). On ebay, today, I find a small number of these listed - but in the history ("sold") there are none.
According to a list of Schneider-Kreuznach serial numbers, my lens was made around 1959. It has the M42 mount and a preset aperture with 8 blades. It has a nice weight and feels very well made.

My lens came with a pretty stiff focus, so I thought, I'd give it a try to disassemble and clean it. Although I couldn't find any tutorials, these older German lenses are usually relatively easy to disassemble - so I gave it a try.

Unfortunately, I did not fully succeed: At the end, I was not able to separate the last two pieces to get full access to everything. But I was able to clean and relube most of the lens internals, and able to make a little workaround for the last piece. This gave a huge improvement of the focusing.

I'm starting by removing the nameplate with a rubber tool.

With a lens spanner, I remove the ring that holds the front glass piece.

And I take out the front glass with a suction tool.

This gives access to the ring holding the next glass element.

Now, I can access the aperture from the front.

I continue from the rear side, taking out 3 grub screws that hold the metal ring.

A lens spanner in the outer two holes lets me remove the rear glass.

Now the aperture is accessible from both sides.

Now the front piece can be taken out (I had to wiggle quite a lot!).

This screw is setting the limits to the focus ring.

After loosening this screw, I was able to turn the focus ring until the inner helicoid became free - and further rotating the inner helicoid made it free. Note where exactly it becomes free - and where it exists!

Now, I don't remember what this screw was for (sorry....).

By removing these 3 screws, you can take off the focus ring.

After removing these 3 screws, I was able to remove the back ring.
 

But at this point I was stuck. I have no idea how to separate the inner rotating ring (to which the focus ring is connected) from the rest. Older German lenses (Steinheil, Zeiss Jena, Meyer-Optik) have a second (fine) helicoid for this purpose. But for this lens, it seems that this is not rotating using a helicoid. So, I could not take it off to clean and relube it. But I was able to flush some lighter fluid in between the two pieces, which improved it a lot and it made rotating the focus ring much easier and smoother.

During my attempts to separate the ring, I also tried to remove the helicoid keys. But this did not help, and it was not easy to screw them back on. So I strongly recommend not to try this!!

Due to my failure at this point, I stopped taking pictures of the reassembly of the lens. But since I documented the disassembly in detail, I hope that these pictures are still helpful. 
If you figure out how to separate that last piece, please leave a comment!

In any case, my lens is now in great shape - and it's fun to take pictures with it!

More of my lens repair tutorials can be found here.