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Boudiccalol
Tinkerer
Username: Boudiccalol
Post Number: 1
Registered: 05-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 19, 2011 - 02:45 pm: | 
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Hello everyone!
I have a Cosina lens 35-70mm that came with a Cosina CT-1 Super my aunt gave me. I found that the lens was infested with fungus, so, I tried to dismantle the lens. Perhaps not the wisest decision because I had none experience in that sort of works.
I wasn't able to clean all the lenses, since I couldn't unscrew the name ring, so I decided to give up.
Before that I unscrewed the aperture ring and the back of the lens. When I was trying to assemble it back together I noticed the aperture ring didn't stop at each number. Instead, It slided loosely through them. I think I may have lost some tiny part from the aperture ring, but I don't know which.
I noticed there's a little spring in the aperture ring but I don't know if anything fitted there.
I'll be glad if I find some help.
Kind regards. |
Boudiccalol
Tinkerer
Username: Boudiccalol
Post Number: 2
Registered: 05-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, May 19, 2011 - 03:15 pm: |
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Hi again. I did some extensive research and I guess what's missing is a little ball bearing that should fit in the aperture ring springer, in order to lock the aperture in the proper value. The missing ball is probably inside the lens body, but I can't seem to have a decent grip to unscrew the name ring.
I think I have two ways of solving this:
1 - Find some way of opening the lens front and search for the ball bearing, and at the same time I have the opportunity of cleaning all the fungus.
2- Forget the fungus and the lost ball and buy a new one. I don't know, though, what are the ball's dimensions.
btw I'm portuguese, sorry for my poor english. |
Icr
Tinkerer
Username: Icr
Post Number: 10
Registered: 08-2011
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, July 08, 2012 - 09:38 pm: |
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The front trim ring is metal and glued to the plastic piece with threads. It unscrews. Looks like there was a touch of glue keeping it in place. From there you can get to all the lens elements in front of the aperture. From the rear, the group unscrews, but remember where it was as it is set specifically at at certain distance. It is held in place a stack of spring washers. Take the rear lens mount ring off to get a better grip on it. Don't loose the little ball for the aperture detent. |
Thepurush
Tinkerer
Username: Thepurush
Post Number: 52
Registered: 01-2012
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, October 05, 2012 - 08:04 am: |
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You can find replacement ball in ballpoint pens. Collect a few sizes and try the one which fits,
There is nothing critical abt it but a bigger one wont fit in. And a too small a one will not give u a firm click stops.
In any case you shd make sure that the ball isnt in the lense itself. Chances r rear but it can damage lense. |
Leesobing
Tinkerer
Username: Leesobing
Post Number: 76
Registered: 01-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, October 09, 2012 - 11:43 pm: |
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http://www.bigeye.url.tw/big5/d_cosi35_70.htm
here has picture to show how to unscrew the name ring and bear ball place, holp to help you. |
John_shriver
Tinkerer
Username: John_shriver
Post Number: 93
Registered: 12-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, October 11, 2012 - 06:54 pm: |
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There are folks who sell 1mm, 1.5mm, 2mm, etc bearing balls on eBay, in a bag, cheap. They are SO easy to lose. |
