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Wernerjb
Tinkerer
Username: Wernerjb
Post Number: 252
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 03, 2008 - 03:53 am: | 
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More incidentally I stumbled into the business of opening and repairing lenses after getting an inoperative Exakta branded zoom (a Cosina) lens a while ago. With the assistance of skilful forum people I felt encouraged to get it back to working properly again.
Meanwhile I have tried to expand my knowledge in the inner make-up of zooms, bought some junkers, experimented a bit and was confronted with a number of problems. Maybe someone has practical answers to these questions.
#1: What are the reasons for single middle elements of a lens group to develop haze or fog-like stains (look definitely different from fungus) while the other lenses are pristine?
#2: What is a safe method of cleaning a single lens elements without touching it (and leaving traces of a fingerprint on the lens edge)?
#3: Is there anything more practical (and cheaper!) than the lens suction cups from microtools for safely handling glass elements during assembly or reassembly?
#4: Especially the rearmost lens group of zooms usually contains several almost identical elements that can easily be mixed up or mounted upside down. How can this sort of error be prevented?
This question may sound a bit simplehearted, but just imagine while being in the process of putting everything back again the phone is ringing ... (or, what can be worse, you hear your wife calling your name with some emphasis indicating there's something brewing ...).
W. |
Rick_oleson
Tinkerer
Username: Rick_oleson
Post Number: 503
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, February 03, 2008 - 09:55 am: |
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i hate zooms in general and can't answer all of your questions....
to keep straight the which-side-goes-in-frist question, i usually plant a fingerprint right in the middle of each element before i remove it, and use the fingerprint to tell me which way goes on the outside - then clean it off with a microfiber cloth on reassembly. as far as telling which lens is which, i lay out each ring and lens element in a row in the order they came out. i also lay them fingerprint-side-up.
when tackling something complex, i first make sure that i have at least a couple of hours of uninterrupted time, and i don't answer the phone. if i was out when it rang i would not answer it, i don't consider the phone to have priority over my life. as for my wife, i try to arrange in advance that she knows what i'm doing and will wait til i'm done unless there's a genuine emergency. if there IS a genuine emergency, it may be more important than the lens.
i bought a package of cheap disposable cotton gloves for handling lens elements (once i have the one required fingerprint in place) |
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