Archived posting to the Leica Users Group, 2001/05/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]John: All I know is that my 1954-vintage 50mm F1.5 Summarit ended up with a very scratched front element after repeated cleanings with lens tissue over many years of use (1969-1975). It was pristine when I found it in my parents basement. If I'd bought and used an E41 UV filter, it would have stayed pristine. Yes, reflections and possible flare are reduced without the UV filter on there. But be careful! This article http://www.f32.com/articles/article.asp?artID=102 contains the following quotation: "Filters however, regardless of how well they are made, unfortunately do influence the photographic image adversely. Lens performance is slightly diminished, and due to the introduction of two more glass to air surfaces, the possibility of internal reflections and flare is much greater. Therefore some lens manufacturers design their lenses such that they will not transmit any UV light. All the lenses for the Leica cameras for instance use a special UV absorbing material, Absorban, to cement the various lens elements together. In lenses without cemented elements, this is assured via different means. The result is better lens performance without the necessity of a UV filter." My question is: for how long has Leica been using Absorban to cement the various lens elements together? Would M lenses dating to the 1960's have used this UV absorbing material? What about my first M lens acquired in 1965 [Summarit 50mm / f1.5]? Is the author of the article fair in suggesting that Leica lenses perform better without than with UV filters? John Hudson Vancouver, BC Mark Bohrer www.kokophoto.com Pro mountain bike racing on the web