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Billmartins
Tinkerer
Username: Billmartins
Post Number: 17
Registered: 08-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, January 04, 2012 - 11:29 am: | 
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I've had this Zeiss 50mm 2.8 Tessar lens with an aluminum body which is an M42 Screwmount and used it once or twice. It has given some good images, but [won't] I can't stop-up the aperature setting ring beyond f/5.6. Does this indicate a jumped thread on the helicoid? |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 1166
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, January 08, 2012 - 04:10 pm: |
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It might have been disassembled and not gotten back together right. When you set the aperture blade cage back into the barrel, you not only have to get all of the blade pins into the slots, but you have to get each blade into the RIGHT slot. With, say, 10 blades, you have one chance in 10 of randomly getting this right if you're not looking carefully. If you get it off by one blade, then it will all work fine except that the aperture ring will stop short at one end or the other of its travel. It would be fairly easy to overlook this, if someone were cleaning it to sell and didn't use it after reassembly. |
Billmartins
Tinkerer
Username: Billmartins
Post Number: 18
Registered: 08-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, January 20, 2012 - 03:36 pm: |
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Hi Rick, thanks for replying to this post. I'am working this from our public library as my computer is down, hence the delay for this update. I should have initially mentioned that the lens appears to have sustained some damage as evidenced by the filter ring being bent out-of-round slightly. BTW I checked your repair CD and didn't see this lens among the ones on the disk. I'd like to get a file showing some internal views of this one before making a stab at straightening this one out.
Best |
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