Jena tessa's 50/2.8 disassembly

[ProbablyPasta]

Hi all,

i recently bought a beautiful jena-tessar 50mm f2.8 exakta mount lens. The lens work fine, except for the fact that the focusing helicoid is stiff as all heck. I’ve done some work on lenses and cameras before, but those were all cool-if-i-fixed-it-whatever-if-i-don’t situations. I’d rather not ruin this lens by taking it apart and not being able to put it back together properly.

Tl:dr-> I have to get to the focusing helicoid to clean and lubricate it. I do not know how, and what to watch out for.

Does anyone have any good insights/guides i could follow?

Thanks in advance

 

[Rekusu]

This link may give you some idea of what to expect:

Repair: Carl Zeiss Jena Tessar 50mm f/2.8

Hello, everybody! Did you watch the archery event at the Olympics? The accuracy of the contestants are amazing, I am amazed by how they could calculate the precise tension, direction and distance r…

richardhaw.com

 

[ProbablyPasta]

This link may give you some idea of what to expect:

Repair: Carl Zeiss Jena Tessar 50mm f/2.8

Hello, everybody! Did you watch the archery event at the Olympics? The accuracy of the contestants are amazing, I am amazed by how they could calculate the precise tension, direction and distance r…

richardhaw.com

thanks for your reply! wish i read it sooner though. especially the part about getting the helicoids to mate again, as i have incorrectly marked mine. are there any diagrams on how this lens is supposed to fit together? i’ve seen a youtube video on getting the helicoids to mate again but i can’t get it to work since their lens is a different model

 

[Rekusu]

I cannot offer any advice. I have only done a partial disassembly of one (test) zoom lens and did remove the helicord. Took care to mark the parting position but found that a/ getting it to mate again was very, very challenging and b/ even with the start position marked, it did take a number of attempts to get it back to the original position when fully wound home.

 

[Hunter_Compton]

If it's built like my similar Biotar 58mm f/2, which I suspect that it is, then there should be a spanner ring at the rear inside the bayonet mount. Removing this ring, there should be a shim ring (note which side faces forward) and then the lens capsule should slide out the front leaving the helical and aperture release button behind.