Repairing c/y Carl Zeiss Planar 100/2

[ks73]

I wanted to share my little adventure

I bought some time ago Carl Zeiss Planar 100mm 2.0 AEG as faulty. There was something loose inside the lens and pictures were certainly not good. Also the lens barrel was bent. The barrel is made of such thick metal, it must have been quite a hit. It was not possible to focus to infinity, but only to a few meters at most.

Pictures turned out like this:


First I fixed the bent filter thread, using instructions found here (thanks Lloydy!): http://forum.mflenses.com/dented-filter-ring-repair-tool-t72304.html

Then I watched maybe dozen times this assembly video to figure out what to do: https://www.youtube.com/watch?v=Awz5saMnpyg

I decided to approach the front way. I unscrewed the name plate ring with rubber tool, then very carefully unscrewed the front lens group (three lenses) It comes out in one piece. I immediately noticed that the last lens of the front group and the ring locking it were completely out of their place. I set the lens to its place and screwed back the locking ring. It was easy to tighten it with spanner tool. Then I put back the front group and name plate (and went outside breathing for a minute).

Here are the test pictures (no pp, only exposure and wb adjusted):

#1 (WO):

#2 (f2.8 or f4):

#3 (f8):

There is only one thing, the lens focuses way past infinity. When the focus is at inf, the scale is at ~10m. Could it be that the barrel is on the wrong thread? The assembly video I linked shows clearly that there are several places to start screwing the focusing helicoid (at 2:30). I must say that I may not be brave enough to do a repair that! :1lg)

[Jiaming]

The kitty shot is great! Calibrating infinity is just a trial-and-error procedure and indeed might take quite some time. But I believe it is feasible to do it at home. Remember the angle to turn from optical infinity to engraved infinity, and mark the position where the focusing barrel screws out. Turn the barrel for the angle from marked position, and screw back in, then you should be almost there.

[poilu]

great job!

[ks73]

Thank you!

Jiaming: I am not sure how much I should disassemble the lens before I can screw out the focusing barrel. Do you have some tips for that?

[Lloydy]

Great job, and obviously the lens was worth saving. I'm still using that little jig for bent filter threads, it must have done a few now.

[Jiaming]

[Layer-cake]

heres a good video that helped me out a while back

https://www.youtube.com/watch?v=Awz5saMnpyg

[Gardener]

Great job, I've seen that video too when I was thinking/looking for info on how to approach 85/1.4.