The lenses were clear when new. The yellow reflections on the front is the coating, which was also normal for these lenses.
ppro > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED]]On Behalf Of Marcus > Sent: Sunday, February 17, 2002 5:01 PM > To: [EMAIL PROTECTED] > Subject: RE: Takumar lenses: Yellow coating or radioactive decay??? > > > > The lens I referred to is the 50mm f1.4 Super-Takumar > w/49mm front thread. It the yellow color is from > Lanthanum doped glass, than were these lenses clear > when new or yellow. And maybe I'm not understanding > properly, but you say the lens transmits yellow which > is certainly correct, but reflections off the front > elements are very much yellow. > > --- "Paul M. Provencher" <[EMAIL PROTECTED]> wrote: > > If the lens is not a 50mm f/1.4 or 35mm f/2.0 (49mm > > filter thread) Super-Takumar or Super-Multi-Coated > > (SMC) Takumar, you can > > attribute the yellow reflections on the glass to > > coating, although most SMC lenses have multiple > > coating colors. > > > > If you have one of the aforementioned lenses, and > > the glass TRANSMITS a yellowish tint, then you > > indeed have a lens that is PROBABLY > > this way because of the rare earth elements used in > > the construction. > > > > It is possible that the adhesive used to cement lens > > groups can also cause this problem. But with these > > two lenses, this is almost > > never the case. > > > > Read the archives - there should be tons of > > discussion about this topic. > > > > ppro > > > > > -----Original Message----- > > > From: [EMAIL PROTECTED] > > > [mailto:[EMAIL PROTECTED]]On Behalf Of > > Marcus > > > Sent: Sunday, February 17, 2002 3:01 PM > > > To: [EMAIL PROTECTED] > > > Subject: Takumar lenses: Yellow coating or > > radioactive decay??? > > > > > > > > > > > > Can someone please settle this once and for all? I > > to > > > have a Super-Takumar that has yellow tinged > > elements. > > > > > > I have been told by multiple people that this is > > just > > > the old coating. I have also read several sources > > on > > > the Internet that state that this is the result of > > the > > > radioactively doped glass decaying. With the > > profound > > > amount of hear say that occurs on the Internet, it > > is > > > hard to know who to listen to. > > > > > > One hint that makes me believe the "decay" answer > > is > > > that while the front element reflects yellow while > > the > > > rear element reflects purple. I would not think > > that > > > they would use two completely different coatings > > on > > > one lens? > > > Yahoo! Sports - Coverage of the 2002 Olympic Games > > > http://sports.yahoo.com > > > - > > > This message is from the Pentax-Discuss Mail List. > > To unsubscribe, > > > go to http://www.pdml.net and follow the > > directions. Don't forget to > > > visit the Pentax Users' Gallery at > > http://pug.komkon.org . > > - > > This message is from the Pentax-Discuss Mail List. > > To unsubscribe, > > go to http://www.pdml.net and follow the directions. > > Don't forget to > > visit the Pentax Users' Gallery at > > http://pug.komkon.org . > Yahoo! Sports - Coverage of the 2002 Olympic Games > http://sports.yahoo.com > - > This message is from the Pentax-Discuss Mail List. To unsubscribe, > go to http://www.pdml.net and follow the directions. Don't forget to > visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
