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Werner J. Becker
Tinkerer
Username: Wernerjb
Post Number: 11
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 10, 2006 - 03:29 am: | 
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Have just successfully reassembled a Tamron zoom lens (28-135) that had been given to me by someone who said it was in a "state of irrepair". I got it back together again after some trial and error, there was nothing to lose anyway. Now I feel keen enough to try cleaning the oily blades of a Panagor one touch macro zoom (3,5-4,5/35-135) which otherwise is in pristine condition; unfortunately this one seems more complicated to open. Does anybody more experienced with lenses know how to reach for the aperture? From the front (which I would try first) or from behind? What about tricks and pitfalls? Your help will be greatly appreciated, W. |
Henry Taber
Moderator
Username: Henry
Post Number: 13
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 10, 2006 - 07:45 am: |
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Werner,
I think the Panagor and Kiron are the same lens. Check my Kiron lens article to see if it looks the same. The article won't help you much except to dial in the focus, but I also have a few more photos of the lens disassembled to the diaphragm.
Henry |
Werner J. Becker
Tinkerer
Username: Wernerjb
Post Number: 12
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, August 11, 2006 - 03:17 am: |
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Thank you for your help, Henry.
Yes, the lenses are pretty much the same, so I'd be interested in the photos showing lens disassembly. Would it be possible to send them to me in an e-mail ?
NB: The Tamron zoom mentioned in my starting article came in two parts, and it was given to me because I have been using another specimen on one of my SRTs for ages! On reassembly of the "new" one I found it difficult to find the correct point for wide angle sharpness (28mm !). There is still a slight difference at infinity between the wide angle and the tele end of the zoom range. But I guess this cannot be corrected, as my "old" one in use has always behaved like that from the start; the pictures it takes are excellent, W. |
Werner J. Becker
Tinkerer
Username: Wernerjb
Post Number: 13
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 16, 2006 - 07:29 am: |
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Henry,
I have successfully disassembled the zoom lens but I do not understand how the middle part of the optical system comes off (in your pictures showing "exploded view" the part or ring I am referring to is the one carrying the lens assembly and has got four round holes in the outer rim, it is covered by the round two-holed retainer ring.)
With this part in the way the aperture mechanism is inaccessible; I hope you can give me a hint how to proceed, W. |
Henry Taber
Moderator
Username: Henry
Post Number: 18
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 16, 2006 - 10:09 am: |
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Been so long since I've had one open... and I'd hate to lead you wrong. But, giving those two disclaimers, I'm thinking there are setscrews on the outer perimeter.
Henry |
Werner J. Becker
Tinkerer
Username: Wernerjb
Post Number: 14
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, August 16, 2006 - 12:24 pm: |
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With a bit of luck I found the solution to that problem: no setscrews, a thread around that four-holed part, the holes are for ventilation AND for inserting a tool. Underneath the aperture module there is another lens (element/group), like the aperture blades it has tiny oily specks will have to be given extra care as it looks delicate. I am going to remove it has before swabbing the blades.
Reassembly (certainly not today!) will probably be another challenge, W. |
Werner J. Becker
Tinkerer
Username: Wernerjb
Post Number: 15
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 17, 2006 - 09:17 am: |
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Have everything back together again. What a fine lens this is!
During reassembly (which in the end was easier than I had thought) I routinely cleaned all lens surfaces and looking the cotton swabs afterwards showed I was right doing so. My theory is that in a zoom lens with just one ring for both sharpness and zoom a lot of air flow meets the lens surfaces when zooming, and if that air isn't clean or dry the glass catches a lot of dirt. Maybe it's got to do with different temperatures of glass surfaces and air.
To all those who follow my example and give their inoperative zoom lenses a second chance: the aperture blades are a lot thinner and prone to be bent during cleaning than those of old rangefinder cameras. The linkages to it are also not very sturdy. Leave them as they are, even if they seem to need rebending. Take down what you see before you take it apart, this is very useful for reassembly. This is to say you have to work with great care and patience, especially when repositioning the helical ring or the aperture module. Focus adjustment is not too difficult if you follow Henry's article. |
