Archived posting to the Leica Users Group, 2007/11/10

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Subject: [Leica] Img: Radioactive lens fix works
From: philippe.orlent at pandora.be (Philippe Orlent)
Date: Sat Nov 10 08:52:29 2007
References: <86E01E09-09CE-4A4A-A35C-A8DCA6E7DD5B@comcast.net>

Len,
Impressive. And I believe you ofcourse.
But I don't know if those photos prove your point. Both seem to be  
taken in different lighting situations so is there much interest in  
comparing them?
Philippe



Op 10-nov-07, om 17:21 heeft Leonard Taupier het volgende geschreven:

> For those of you interested in the Pentax 50mm yellowing problem,  
> Here are photos taken before and after 116 hours exposure to UV  
> light to reverse the yellow cast problem due to the radioactive  
> element Thorium in one of the lens elements.
>
> Before photo. Lens has brownish, yellow cast.
>
> <http://gallery.leica-users.org/v/LeonardT/Pentax/ 
> Takumar_50_2.jpg.html>
> <http://tinyurl.com/233emd>
>
> Here is a photo taken after only 116 hours of being exposed to UV  
> light. The exposure was to 16 hours of sunlight and 100 hours of UV  
> from a blacklight.
>
> <http://gallery.leica-users.org/v/LeonardT/Pentax/ 
> Takumar_116hrs.jpg.html>
> <http://tinyurl.com/2bx7do>
>
> I did not expect any improvement this quickly if at all. I'll  
> probably keep the lens in front of the blacklight for a few days  
> more to see if there is any further improvement.
>
> Thanks for your interest.
> Len
>
>
>
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>


Replies: Reply from henningw at archiphoto.com (Henning Wulff) ([Leica] Img: Radioactive lens fix works)
Reply from len-1 at comcast.net (Leonard Taupier) ([Leica] Img: Radioactive lens fix works)
In reply to: Message from len-1 at comcast.net (Leonard Taupier) ([Leica] Img: Radioactive lens fix works)