Repairing a Meyer-Optik Görlitz Orestegor 200mm f/4 lens (Zebra version)

 

The Meyer Optik Görlitz Orestegor 200mm f/4 was released in 1964, featuring 5 elements in 5 groups and a preset aperture with 15 blades. In 1970, it was renamed "Pentacon 200mm f/4" and over the years, its appearance was adopted to the trends of the 1980's. It uses an adapter system for different mounts, including M42 and Exakta (the same adapters were later also used for the Orestor 135mm f/2.8 lens) - mine is the Exakta version.

The Orestegor 200mm f/4 is already pretty sharp wide open, and excellent when stopped down to f/8. My favorite feature of this lens is the 15-bladed aperture which produces a beautiful rendering of out-of-focus lights and a very smooth bokeh.

The only trouble with my lens was a significant amount haze (and possibly some fungus?), 

plus a slightly stiff focus and some oil on the aperture blades. The latter was not (yet) a problem, but once I open the lens this will, of course, be cleaned.

General Recommendations

First, you need tools like a lens spanner and (good!) screw drivers. For cleaning the metal surfaces, I am using cotton swabs and high percentage Isopropyl Alcohol (I got 91%) for all metal surfaces and the glass - and lighter fluid (Zippo) for cleaning the old grease in the helicoids). You also need helicoid grease.

I strongly recommend to take photos of every single step along the way. Whenever I take off a piece, I first try to understand how it was connected and what it did, and then I clean immediately all of its accessible surfaces with alcohol-soaked cotton swabs. 

Disassembly

I'm starting from the back side. The mount adapter is easily removed.

With a lens spanner, the rear glass is removed.

This already gives access to the aperture blades. But I recommend cleaning them a little later. I proceed with the front side.

At this point, I cleaned the aperture blades using Zippo lighter fluid and plenty of cotton swabs - again and again.

At this point, I am not going into the details of how to disassemble the helicoids - if you have never done this before, please read some other lens tutorials first. The most important aspect is to keep track (notes! photos!) of how the elements were sitting and at which position the helicoid comes off.

That's it! The aperture is clean, the focus very smooth, and the glass is clear.

And the beautiful Orestegor 200mm f/4 is ready for new adventures...

More of my lens repair tutorials can be found here.