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[OM] Separated Zuiko 250/2, was: Inside the Zuiko 300mm F4.5

Subject: [OM] Separated Zuiko 250/2, was: Inside the Zuiko 300mm F4.5
From: usher99@xxxxxxx
Date: Tue, 10 Nov 2009 14:21:11 -0500

Wow this list is fast.   I was to provide the same suggestion. I think 
they recoat as well, as the heat will vaporize some coatings.  They did 
get back to me regarding a fungus etched lens--wasn't worth the cost to 
fix.  250 f2 maight be another story.
http://www.focalpointlens.com/fp_intro.html

Even a minor repolishing can wreck the optics according to Zeiss: from 
the Zeiss site:


"When a lens is “re polished” it is not the same as Zeiss intended. One 
of the greatest parts of the lens makers art is the final polishing. 
Every lens element was taken through a process of abrasive surface 
removal, starting with the final raw blank of optical glass. With each 
step the abrasive used became progressively finer. This entire process 
was calibrated so that when the final polish step was finished the lens 
would be at the optimum dimensions for the design within a few 
millionths of an inch. Just how fine was the final polish Zeiss used? 
Zeiss had, and probably still has, large underground tanks which were 
isolated from even the slightest vibration. These tanks contained 
absolutely pure water containing rouge (iron oxide), that had been 
ground to the final possible fineness. After a period of years the 
liquid in the tank would be carefully removed from the top. When this 
liquid was evaporated an incredibly fine abrasive would remain and this 
is what was used to apply the final polish to Zeiss lenses. This is how 
very fine the surface of a Zeiss lens is. It is fine within a millionth 
of an inch. When a lens is “re polished” in a repair shop the degee of 
fineness of the lens surface that results from re polishing there, when 
compared to the original Zeiss surface is like comparing a bolder 
strewn field to the surface of a mirror. Basically, a Zeiss lens that 
has been re polished is no longer a Zeiss lens; it has been turned into 
ordinary junk."



Mike






































I posted a note to the Yahoo camera repair group on re-cementing
elements and got this response
-----------------------------------------------------------------
Yes, go here:

<http://www.focalpointlens.com/fp_services.html#lens_separation>

If Zuiko used balsam, it should be repairable.

If Zuiko used UV epoxy, well, it may be hard to separate the lens
doublet.  Maybe even impossible.

Good luck



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