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

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: [Leica] Img: Radioactive lens fix works
From: len-1 at comcast.net (Leonard Taupier)
Date: Sat Nov 10 09:02:46 2007
References: <86E01E09-09CE-4A4A-A35C-A8DCA6E7DD5B@comcast.net> <889076F9-8162-4953-B151-D511A0166969@pandora.be>

Hi Philippe,

Both photos were taken in natural window light but I see a slight  
difference in the color temperature. I can see the lightening of the  
color quite easily in any light though. It has been overcast here the  
last couple of days but Tuesday will be a sunny day and I plan on  
taking some color slide photos then.

Len


On Nov 10, 2007, at 11:52 AM, Philippe Orlent wrote:

> 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
>>
>>
>>
>> _______________________________________________
>> Leica Users Group.
>> See http://leica-users.org/mailman/listinfo/lug for more information
>>
>
>
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information


Replies: Reply from jhnichols at bellsouth.net (Jim Nichols) ([Leica] Img: Radioactive lens fix works)
In reply to: Message from len-1 at comcast.net (Leonard Taupier) ([Leica] Img: Radioactive lens fix works)
Message from philippe.orlent at pandora.be (Philippe Orlent) ([Leica] Img: Radioactive lens fix works)