Archived posting to the Leica Users Group, 2002/03/22
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]In a message dated 3/20/02 10:56:46 PM Eastern Standard Time, msmall@infi.net writes: > Leica has never owned a glass works. See the introduction to Rogliatti's > lens book I am uncertain as to the edition of Rogliatti's lens book that Marc has been reading but on page 6 of my Rogliatti lens book he writes: "Especially the progress in melting optical glasses of special properties has affected many modern designs and it's the choice of glass materials not available two or three decades ago, which makes the real difference between lenses having quite a similar lens scheme.......Since World War Two a number of high index glass with reduced or even anomalous color dispersion has [sic] been introduced and a good deal of these glasses, e.g. the so-called "lanthanium [sic] glasses", now used throughout the optical industry all over the world was originated in the glass laboratory at the Leitz factory in Wetzlar and was developed upon special request of our designers!" And our redoubtable Erwin Puts writes at page 23 of his Leica Lens Compendium: "During the war Leitz introduced single layer coating (around 1941) and after the war new glasses became available, many of them specifically researched in the Leitz glass lab founded in 1949. In the past the optical designers had frequently said that they could get better correction of aberrations if they could use a glass with specific properties. These glasses however did not exist and to have to wait and see if and when Schott, or other manufacturers, produced the glass so eagerly awaited was not in the interest of Leitz." Obviously then, Leitz glass works invented and produced new glasses, most importantly, LaK 9, tha lanthanum crown glass that was the basis of virtually all of the new Leitz designs from the 1950s through the mid-1960s. Because they were needed and no one else produced them (see my last post). Seth LaK 9 - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html