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Aeroxy
Tinkerer
Username: Aeroxy
Post Number: 1
Registered: 06-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 20, 2008 - 06:12 pm: | 
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Couples months ago, for no reason, and I do not know what causes, even I change my lens¡¯ A /M switcher to the M position, it cannot adjust the diaphragm. I open the lens to withstand a profile of the firing pin so I can adjust it again with the A position. But later, I found that it only regulation from F1.8 to F4, the aperture small than the F4 virtually has not been changed, continues to maintain the size of F4. Therefore I open the lens again, made the installation look like the original. I found the M file can be used again, not the conventional 'can', but need to first stall transferred to M, laws aperture size, than switch to A (damping will become great), in the process of changed to the A position, the aperture will shrink. However, if I want to change the diaphragm to less than the F4 aperture, I have to switch twice, the first adjustment to the A will make the diaphragm shrink to F4, and the second is scheduled to be contracted aperture. Of course, sometimes it is failed, than I got to repeatedly try several times. Thereby I find it is very inconvenient, particularly evident on the spider. So I once again open the lens of the camera, to shoot that the lens¡¯s inside configuration. Maybe there are some great master might be able to find the problem of my lens, and told me how to repairs. Oh, of course, very grateful to the friends who patiently read this passage.
(I don't know how to pose a picture, and the attachment is limited to a max 450 pic.) |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 602
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 20, 2008 - 08:37 pm: |
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Your lens diaphragm probably needs to be cleaned. Oil gets into the mechanism, then dries and gets sticky and then the blades do not close properly. For cleaning, the lens needs to be taken apart.
From your description, I am guessing that maybe you are talking about a 50 or 55mm f/1.8 Takumar? I have a disassembly sketch for a 55/1.8 Super Tak, it is not very much information but it might help. If you do not have a Takumar, though, this sketch will not help; different makers used different construction. |
Aeroxy
Tinkerer
Username: Aeroxy
Post Number: 2
Registered: 06-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 21, 2008 - 02:55 am: |
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It is pentacon 50/1.8, I believe it is quite similar. |
Aeroxy
Tinkerer
Username: Aeroxy
Post Number: 3
Registered: 06-2008
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, June 21, 2008 - 03:00 am: |
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http://forum.manualfocus.org/viewtopic.php?id=10842
You may click this link, it is also post by me but with the picture. I think my mechanism is clean, because the diaphragm can change by using the pole easily. |
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