Archived posting to the Leica Users Group, 1996/09/14
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]The Schneider Xenogon was designed in 1925 by Tronnier; like the Zeiss Biotar of Merte, it is an assymetrical derivative of the classical double-Gauss design, Rudolph's Planar of 1896. The Zeiss Biogon was designed by Bertele in 1934; it was derived from his Sonnar design, a modified triplet. There is little in common between the Xenogon and the Biogon, though the latter design was used by Mandler as the basis for the Elcan and the 35mm Summilux, bringing us back to the heart of this thread. The assymmetrical double-Gauss concept was the basis of an entire family of Leitz lenses, the Summar, Summitar, Summicron, the Summarit/first Summilux, and the first Noctilux. Marc msmall@roanoke.infi.net FAX: +540/343-7315 Cha robh bas fir gun ghras fir!