Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,203   Posts: 1,531,650   Online: 1164
      
Page 2 of 2 FirstFirst 12
Results 11 to 12 of 12
  1. #11

    Join Date
    Mar 2005
    Shooter
    Multi Format
    Posts
    3,355
    Thorium, Bruce, not Lanthanum. See http://home.earthlink.net/~michaelbr...aeroektar.html

    Another misconception that just won't die.

  2. #12

    Join Date
    May 2006
    Location
    Northern Aquitaine
    Shooter
    35mm RF
    Posts
    4,913
    Quote Originally Posted by Dan Fromm View Post
    Thorium, Bruce, not Lanthanum. See http://home.earthlink.net/~michaelbr...aeroektar.html

    Another misconception that just won't die.
    The Briggs piece is brilliant but deals only with Aero-Ektars. There is a later generation of 'hot' glass where the radioactive component is (according to Dr. A. Neill Wright, one of the authors of the original BJP paper) the result of using a radioactive salt to bleach ferric and ferrous salts to colourless ferrates; these lenses, including several Takumars, are primarily alpha particle emitters.

    At least, that is my recollection, but on checking some past correspondence with Michael Briggs I find that he disagrees. As both he and Neill know vastly more about this than I, and base their observations upon actual research, all I can do is step back and provide both points of view. I had forgotten, but apparently it was a piece I wrote in Shutterbug, about Neill's observations, that got Mr. Briggs interested in 'hot' lenses. I've always said that a good teacher wants his pupils to be better than he is, so I must have been a good teacher on this occasion!

    I once got a convincing autoradiograph from standing an Aero-Ektar on a sheet of Polaroid -- in less than 24 hours, as I recall, though I've forgotten now (it was a very long time ago). Neill also found that some Apo-Lanthars are 'hot' and others aren't, which is quite intriguing.
    Last edited by Roger Hicks; 08-17-2007 at 04:36 AM. Click to view previous post history. Reason: Checked correspondence
    Free Photography Information on My Website
    http://www.rogerandfrances.com

Page 2 of 2 FirstFirst 12


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin