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Message |
    
Fernandel
Tinkerer
Username: Fernandel
Post Number: 1
Registered: 11-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, November 08, 2007 - 04:41 am: | 
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i have this 50mm f1.8 pentacon on my praktica mtl3 and now the blades are stopped and diafragm stays wide open at 1.8, i can turn ring to other position but nothing happens elsewhere in auto or manual position... |
York_praktica_fan
Tinkerer
Username: York_praktica_fan
Post Number: 20
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, November 09, 2007 - 05:26 am: |
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Fernandel
this is a common problem with the pentacon (and other DDR lenses of this period)
Unfortunately only a full strip down will solve it.
This will be expensive if done professionally (I can recomend some UK based and one Canada based pro)
Try search the internet for guides to cleaning lenses - i think there is one on "Manual Focus Forum"
regards
Stephen |
Fernandel
Tinkerer
Username: Fernandel
Post Number: 2
Registered: 11-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, November 10, 2007 - 01:09 pm: |
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So it should be a CLA problem only?
i was thinking there was something broken...
thanks a lot!!!!!
Stefano
i will serch for the for the internet guides.. |
York_praktica_fan
Tinkerer
Username: York_praktica_fan
Post Number: 22
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, November 11, 2007 - 10:54 am: |
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Stefano
yes a CLA should solve the problem.
I believe it is to do with the quality of the lubricants that were available in the DDR at the time. Over time the grease migrates from the helicoid and ends up on the blades, causing them eventually to seize up.
I've had this problem on several Pentacon 50mm, Zeiss Pancolar 50mm and Zeiss Tessar 50mm, and I have read over similar probelms with other DDR lenses from this period.
I hope tthe search goes well - I've not found a strip down diagram for the pentacon but I can point you towards pages for the Tessar which may be similar.
regards
Stephen |
