How to disassemble post war ZO Sonnar 85/2 in Contax rf mount?

simonOWO

simonOWO

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Got this lens in good condition, just need some service with grease, tried to open it but couldn’t. It seems to be easy, 3 screws immediate visible and 3 more hiding under the springing focus coupling, but after removing the mounting mechanism, nothing else moves.

Unlike This thread, Mine seems to be in a different construction: there is no screw on the focus ring. Only 3 on the aperture ring, removing them looses the unthreaded aperture ring, but nothing else.

So this is how far I got.

Any idea or hint would be greatly appreciated!

IMG_0808.jpeg
 
Last edited:
jc031699 said:
This may be more what you are looking at

Kiev Survival Site

Jupiter-12 Lens Dismantle and Clean
web.archive.org

The focus mechanism opens from the front
Click to expand...
This is not the correct answer I'm afraid. The Soviet Sonnar 85 stems from a different (pre-war) family branch and is constructed differently. The Opton Sonnar does come undone at the front, but there are internal screws that keep it from unscrewing. It will move a couple mm and then hit the hidden screw. I had the very same question a while ago. I messaged Chris from Skyllaney and this is what he wrote:

„On the late model Zeiss lenses of this era they started to retain optical block with a hidden internal screw. The screw can only be accesses if you completely dismantle the helicoid. The screw is on the inner helicoid, so the outer helicoid mechanics need to be removed first. Sometimes, with lenses this old there needs to be a heat application to free things up as well. Hope this helps.“

I haven’t gotten any further for lack of trying this. But he should know.
 
lukx said:
This is not the correct answer I'm afraid. The Soviet Sonnar 85 stems from a different (pre-war) family branch and is constructed differently. The Opton Sonnar does come undone at the front, but there are internal screws that keep it from unscrewing. It will move a couple mm and then hit the hidden screw. I had the very same question a while ago. I messaged Chris from Skyllaney and this is what he wrote:

„On the late model Zeiss lenses of this era they started to retain optical block with a hidden internal screw. The screw can only be accesses if you completely dismantle the helicoid. The screw is on the inner helicoid, so the outer helicoid mechanics need to be removed first. Sometimes, with lenses this old there needs to be a heat application to free things up as well. Hope this helps.“

I haven’t gotten any further for lack of trying this. But he should know.
Click to expand...

I think both of you might be correct, in my particular case, I don’t need (and also don’t want) to disassemble the optical assembly itself (I presume this is what Skyllane is trying to explain here?)

I just need the optical assembly to come off from the focusing mechanism, so I can service the focusing helicoid.
 
Update:
As in the article, I was able to take the optical assembly out from the front, mine is not so tight.

I just removed old grease and applied new one on the focusing.
 
Last edited:
Got the foto anyway, just realized too much grease was applied, gonna clean some off.

To disassemble the optical assembly, on my particular variant (no set screws on focusing ring, only on aperture ring…)

3 screws here need to be removed.

They stop the optical assembly from rotating out

IMG_5264.jpegIMG_5263.jpeg
 
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