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??? Disassembly of Meyer Primotar 50mm f/3.5 ???
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PostPosted: Thu Jun 27, 2019 2:01 am    Post subject: ??? Disassembly of Meyer Primotar 50mm f/3.5 ??? Reply with quote

I recently purchased a Meyer-Optik Gorlitz Primotar 50mm f/3.5. Cosmetically, it's beautiful. Optically, it has a lot of internal dust and some lint. More importantly, it has the beginnings of two types of internal fungus. This example was manufactured in 1956 or '57.

QUESTION: Is there a link to disassembly instructions for this lens?



PostPosted: Thu Jun 27, 2019 6:05 am    Post subject: Re: ??? Disassembly of Meyer Primotar 50mm f/3.5 ??? Reply with quote

gawn_dijitul wrote:



There you go. An anti-spam measure stops images being produced on first post.


Last edited by Sciolist on Thu Jun 27, 2019 4:24 pm; edited 1 time in total


PostPosted: Thu Jun 27, 2019 1:36 pm    Post subject: Re: ??? Disassembly of Meyer Primotar 50mm f/3.5 ??? Reply with quote

Sciolist wrote:
There you go. An anti-spam measure stops images being produced on first post.


Thank you Sciolist. I was wondering why the image wouldn't show.


PostPosted: Thu Jun 27, 2019 3:44 pm    Post subject: Reply with quote

Welcome gawn_dijitul

You might find useful info here http://forum.mflenses.com/basic-techniques-to-repair-lenses-and-cameras-t32862.html


PostPosted: Wed Aug 28, 2019 4:58 am    Post subject: Diagram Reply with quote

Maybe someone knows where I can find a diagram?


PostPosted: Sun Sep 01, 2019 10:35 pm    Post subject: Reply with quote

I really need to clean this lens.


PostPosted: Mon Sep 02, 2019 11:46 am    Post subject: Reply with quote

gawn_dijitul wrote:
I really need to clean this lens.



I'm not being flippant here gawn, but an idea might be to buy a cheap basket case. Then take it apart without fear, and in the process become the expert in the maintenance of these lenses.


PostPosted: Mon Sep 02, 2019 1:33 pm    Post subject: Reply with quote

Sciolist wrote:
I'm not being flippant here gawn, but an idea might be to buy a cheap basket case. Then take it apart without fear, and in the process become the expert in the maintenance of these lenses.


Great idea. Thank you!!


PostPosted: Mon Sep 02, 2019 4:44 pm    Post subject: Reply with quote

I am not familiar with this particular lens but most German lenses of that era that I have opened were simple. Typically a series of threaded tubes with lens elements sandwiched via flanges. Do you have rubber bezel wrenches? Also will likely need a lens spanner. On some lenses you have to remove an outer tube by removing grub screws. Is most of the issue with the front group? If so I would go at it from the top. So a typical disassembly would be: remove name bezel with a rubber bezel wrench. These can be purchase d from Japan Toy and Hobby. They also sell the lens wrenches. Sometimes they can just be spun off withjust fingertips. But on a lens this old that is unlikely. Less effective but possibly useful would be a homemade system using a plastic tube and rubber sheet, like a latex glove over pvc plumbing chosen to match the diameter of the bezel. Next up would be spinning a lens group out of the outer tube. This is where you would need the spanner. You will see 2 slots on opposites sides of the mounting bezel. Matching the spanner fitting with the groove and the spanner width to the diameter of the bezel. I do not recommend using anything other than a spanner wrench. I have tried scissors and ruined a lens element. Always set up on a clean white sheet of cloth or paper and take care to match orientation of elements when re-assembling. Blue painters tape can be used to mark the side of the lens toward the outside. Do not leave it on for any longer than necessary as it could potentially damage the coating of the lens. Good luck.


PostPosted: Mon Sep 02, 2019 5:22 pm    Post subject: Reply with quote

jamaeolus wrote:
I am not familiar with this particular lens but most German lenses of that era that I have opened were simple. Typically a series of threaded tubes with lens elements sandwiched via flanges. Do you have rubber bezel wrenches? Also will likely need a lens spanner. On some lenses you have to remove an outer tube by removing grub screws. Is most of the issue with the front group? If so I would go at it from the top. So a typical disassembly would be: remove name bezel with a rubber bezel wrench. These can be purchase d from Japan Toy and Hobby. They also sell the lens wrenches. Sometimes they can just be spun off withjust fingertips. But on a lens this old that is unlikely. Less effective but possibly useful would be a homemade system using a plastic tube and rubber sheet, like a latex glove over pvc plumbing chosen to match the diameter of the bezel. Next up would be spinning a lens group out of the outer tube. This is where you would need the spanner. You will see 2 slots on opposites sides of the mounting bezel. Matching the spanner fitting with the groove and the spanner width to the diameter of the bezel. I do not recommend using anything other than a spanner wrench. I have tried scissors and ruined a lens element. Always set up on a clean white sheet of cloth or paper and take care to match orientation of elements when re-assembling. Blue painters tape can be used to mark the side of the lens toward the outside. Do not leave it on for any longer than necessary as it could potentially damage the coating of the lens. Good luck.


Thank you for the very helpful advice.

Rubber bezel wrenches might be necessary... I'll buy a set. I have a good spanner wrench. Some of these old German classics have a pry-off front bezel. This one doesn't seem to unless it's very tight. There are no grub screws. I can't turn the front ring with finger tips alone. So... the next step is rubber bezel wrenches... or... I could superglue my fingertips to the bezel.😁


PostPosted: Mon Sep 02, 2019 7:34 pm    Post subject: Reply with quote

gawn_dijitul wrote:
... or... I could superglue my fingertips to the bezel.😁



Or wear a pair of rubber washing-up gloves and use your thumbs. For the most stubborn bezels I will dab a cotton bud (Q-tip) in wd40 and run it around the gap where bezel meets lens body (into the threads therefore). Then try and loosen each day until it relents. Be as sparing as you can with the wd40 and remember to clean it off once the bezel unscrews.


PostPosted: Tue Sep 03, 2019 2:10 am    Post subject: Reply with quote

Super glue? I wouldn't recommend that. I have used blue tak. It's flexible silly putty like stuff. I form it into a thin gasket, just the right size. It will ooze into the letters . It worked ok. It comes off without damaging the lens.


PostPosted: Tue Sep 03, 2019 3:21 pm    Post subject: Reply with quote

here is an example of a lens spanner wrench:

https://www.ebay.com/itm/Professional-DSLR-Camera-Lens-Repair-Spanner-Wrench-Open-Tool-Sets-3-Tip-Kit-US/383077132435?hash=item59312d2893:g:XIoAAOSwgO9dP9TK


This is the one I have. Its OK.

I don't see an example of the type of bezel wrench set I use but here is a similar set:

https://www.ebay.com/itm/9in1-Camera-Lens-Repair-Tool-Rubber-Set-Ring-Filter-Removal-Spanner-Wrench-DSLR/272698200702?hash=item3f7e14527e:g:C8MAAOSwyZZcoC1R

As far as cheap practice lenses I would try to find a Meyer Domiplan from the same era. They aren't generally well regarded and thus don't command high prices. That plus it being a meye product means systems are likely to be similar.


PostPosted: Tue Sep 03, 2019 3:30 pm    Post subject: Reply with quote

Thank you jamaeolus. I'll have a look at those links.