Archived posting to the Leica Users Group, 2007/11/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Jim, I don't know when they stopped using it. If I find out I'll let you know. Your lens could have been made only a year after mine. Len On Nov 10, 2007, at 12:21 PM, Jim Nichols wrote: > Len, > > Your results in getting the yellow out are impressive. My lens may > look a little darker than your final photo, but not much. Do you > know how far down the model lineup the Thorium element was used? > > Jim Nichols > Tullahoma, TN USA > ----- Original Message ----- From: "Leonard Taupier" > <len-1@comcast.net> > To: "Leica Users Group" <lug@leica-users.org> > Sent: Saturday, November 10, 2007 11:02 AM > Subject: Re: [Leica] Img: Radioactive lens fix works > > >> 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 >> >> >> _______________________________________________ >> 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