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CZJ Tessar 2.8/50 disassembly Log in | Log Out | Topics | Search
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Volunteer
Tinkerer
Username: Volunteer

Post Number: 2
Registered: 03-2011

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Posted on Monday, June 20, 2011 - 12:39 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

I'm trying to repair my CZJ Tessar, but I can't find a proper tutorial as none of the repaired lenses in those tutorials seem to have been built like mine.
I only managed to remove the back and the focus ring and now I'm stuck.
Any advice on how should I proceed if I'm to disassemble it whole?

Here are the pictures:

http://i.imgur.com/XluQn.jpg
http://i.imgur.com/p5Msc.jpg
http://i.imgur.com/1NgeU.jpg
http://i.imgur.com/DOmzn.jpg

I tried these advices, but I don't know how to follow them with my lens as it's not the same.

http://oomz.net/tessar/

http://forum.mflenses.com/how-to-tessar-disassembly-t30506.html

http://forum.mflenses.com/viewtopic.php?t=21037&view=previous

I want to clean inner glass element as is dusty. Aperture blades seem clean.
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Steve_s
Tinkerer
Username: Steve_s

Post Number: 180
Registered: 07-2006

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Posted on Tuesday, June 21, 2011 - 12:43 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Unscrew the front serial-number trim using a friction tool (e.g. a flat disc of rubber and a suitable bottle-cap, or a rubber bung). You should then see a couple of spanner-slots. Use these to unscrew the front optics (2 elements). You probably won't need to get between them, but if you do, the front element will be held by a conical black-painted ring (friction tool again).

Leave the rear-element in the lens barrel. You can clean it easily without removing it.
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Volunteer
Tinkerer
Username: Volunteer

Post Number: 3
Registered: 03-2011

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Posted on Tuesday, June 21, 2011 - 09:38 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

I love this site. :-)
Thank you very much. I actually didn't believe I was going to manage to unscrew the front, but I did. I cleaned everything I wanted and now, of course, there's another problem - how to reassemble the damn thing? And the second one - with what and where ecaxtly to lubricate the focus ring?
First thing first - reassembling. I took photos of every part of the lens. How to correctly put them together?
All parts:
http://i.imgur.com/0DJ49.jpg

Close up parts 2,3,4
http://i.imgur.com/j4gsk.jpg

Close up part 7
http://i.imgur.com/aFL0M.jpg

Close up part 6
http://i.imgur.com/eDe5k.jpg

Close up part 5
http://i.imgur.com/EdQG3.jpg
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Steve_s
Tinkerer
Username: Steve_s

Post Number: 181
Registered: 07-2006

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Posted on Wednesday, June 22, 2011 - 12:39 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

You will find dozens of threads on this and other forums on what grease to use for lenses. What you can use depends on what you can get where you live. Use the lightest you can, particularly on the fine thread in the focus-mount.

I see the lens is a 'semi-auto'. I haven't dismantled a semi-auto Tessar, but I've attached a couple of pictures of a semi-auto Biotar which show where 3 of the screws (enclosed in '4' in your first picture) fit. The one with the plain section on its end is obviously the focus-stop screw.




Assembly of the helical/focus-mount on these semi-auto Zeiss lenses is different to virtually every other lens you will meet, and very tricky if you didn't make certain notes when you took it apart, in particular the position where the inner helical disengages from the outer, and the position of the parts when the inner helical disengages from its guide in the mount. Ideally, assembly would go as follows: -

1. Assemble the inner helical(7) to the outer helical(5) at the correct position and to a depth you noted during dismantling.

2. Engage the thread on the outer helical with the thread on the mount(6) and screw it on until the helical guide in the mount engages with the slot in the inner helical.

3. Continue screwing the outer helical into the mount until engaged at the position noted before dismantling.

4. Insert the focus-stop screw.

If you didn't make notes you will have to do the job by 'trial-and-error', checking the focus on a camera when you get close. It may not be too easy - take your time and play a CD of calming music!

By the way, there should have been a narrow ring of aluminium on the back of the barrel when you separated it from the helical/mount. This is factory-selected to give correct infinity focus. I don't see it in your pictures, but possibly it is still on the back of the barrel.

Hope it works out!
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Volunteer
Tinkerer
Username: Volunteer

Post Number: 4
Registered: 03-2011

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Posted on Wednesday, June 22, 2011 - 03:30 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Moderator/Admin Only) Ban Poster IP (Moderator/Admin only)

Steve, I can't thank you enough. Thanks for your time, I'll try assembling the damn thing today.

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