Archived posting to the Leica Users Group, 2017/03/13
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Thanks, Steve, you are correct. I have two of these lenses, a SMC 1:1.8/55 Product # 37108, and a Super-Multi-Coated 1:1.4/50 Product #37902. Both are listed on the internet as being radioactive, the 1.4 a little more so than the 1.8. The 1.8 lens is almost clear, while the 1.4 lens is yellowed. From research reported on-line, the yellowing is in the glass of the rear three elements due to thoriumdioxide added to the glass. It can be reduced by exposing these elements to blacklight for about a week. Jim Nichols Tullahoma, TN USA On 3/13/2017 4:23 PM, Steve Barbour wrote: > I recall the yellowing has something to do with a radioactive element in > the glass. > >> Lluis, >> >> After your comment, I took the lens and looked through it toward a cloudy >> sky, and it does have a warm color. Whether it was made that way, or >> darkened with age, I can't really say. I seem to recall that, at one >> time, I placed it in bright sunlight for a few days, to reduce the >> yellowing. The color is not really objectionable to me, but could be to >> some viewers. >> >> Jim Nichols >> Tullahoma, TN USA >> >> On 3/13/2017 2:48 PM, lluisripollphotography wrote: >>> This lens performs very well, as you know I like the rendering of the >>> old lenses. These ones look to me warmer than others with modern lenses. >>> Isn?t it? >>> Lluis >>> >>>> El 12 mar? 2017, a les 22:07, Jim Nichols <jhnichols at lighttube.net> >>>> va escriure: >>>> >>>> I have always been impressed by the results I got from the old Pentax >>>> Super-Multi-Coated Takumar 50/1.4 lens. While watching softball on TV, >>>> I shot a few images from my recliner, not worrying about being square >>>> with the subject. I played with Exposure Adjustment to try to get >>>> somewhere near the correct light. >>>> >>>> I was impressed, once more, by how the lens performed on the X-T2. >>>> >>>> My son, giving me the latest news from his iPhone 7: >>>> http://www.gallery.leica-users.org/v/OldNick/20170312-DSCF0918.JPG.html >>>> >>>> Sharpness, from a crop of details above the fireplace, shot at an >>>> angle, with distortion corrected: >>>> http://www.gallery.leica-users.org/v/OldNick/20170312-DSCF0909-1.jpg.html >>>> >>>> Comments and critiques welcomed and appreciated. >>>> >>>> -- >>>> Jim Nichols >>>> Tullahoma, TN USA >>>> >>>> >>>> _______________________________________________ >>>> 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 >