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Re: [OM] Tokina 80-200mm f2.8 update.

Subject: Re: [OM] Tokina 80-200mm f2.8 update.
From: JOHN DUGGAN <john.duggan10@xxxxxxxxxxxxxx>
Date: Tue, 26 Jan 2010 23:08:43 +0000 (GMT)
Whatever the adhesive is..it is sticky and still seeping out of the doublet. 
Since removing the doublet from it's cell, and removing the filter ring, which 
provided pressure to hold it in place, the signs of de-lamination are far more 
obvious.
It looks like a series of "snowflakes" growing around the circumference of the 
lens
 Really pretty effect when you light the element at a very shallow angle!
Regards
  John Duggan,
     Wales, UK

..........................................................................
--- On Tue, 26/1/10, Charles Geilfuss <charles.geilfuss@xxxxxxxxx> wrote:


> To: "Olympus Camera Discussion" <olympus@xxxxxxxxxxxxxxxxx>
> Date: Tuesday, 26 January, 2010, 18:27
>   Canada Balsam was also used
> for many years to prepare histologic tissue
> sections. It worked well but did tend to yellow over time.
> These days we use
> a product called Permount that dries hard, serving as a
> glue, and is
> optically clear and colorless. It would not surprise me in
> the least if it
> was used to glue optical elements. 
> Charlie
AND Chuck wrote..... 
> On Tue, Jan 26, 2010 at 12:17 PM, Chuck Norcutt <
> wrote: 
> > According to Wiki Canada balsam was phased out as an
> optical cement
> > during the second world war.  Whatever has failed
> must certainly be
> > something different.
> > Chuck Norcutt



      
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