Archived posting to the Leica Users Group, 2003/12/16
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Go pack the 400 Telyt, Tina! After the messages from our Luggers who know, there was no need for me to speak with Ernst Hartmann who called back anyway to confirm that filters are not designed into the optical formula of the 400. On the other UV filter front, this autumn I had the opportunity to test some lenses at a wonderful company in Cambridge Mass. called Optikos (I think it was our own B.D. who put me on to them). They own the EROS machines that test for MTF contrast and resolution. Roy Youman, the optics man who did the tests, had just returned from installing three of these machines in China. I think Doug had it exactly right when he wrote: "In backlit situations, the additional 2 air/glass surfaces will clearly make themselves known, and under other lighting conditions they can cause additional flare too (though you might not notice it w/o controlled tests)." At Optikos during the MTF test of a 7-glass 50/2 Rigid Summicron, I stuck on an E39 UV filter. The read-outs on-axis at f/5,6 at all frequencies through 40 lp/mm with and without filter were identical. That said, Roy confirmed that with a light source within the image area there would be degradation of the image produced at the film plane. Now Ted, please don't get p--sed off at me; I know that what matters is what you do with equipment. And I do. It's just part of my fun to see if the machines agree with what my eye sees. My own experience: I frequently, but not always, fit a UV filter for normal outdoor street photography, landscape where I'm not looking at contre-jour light, and have never noticed any ill effect. Indoor available light shooting, never. Have a great trip, Tina, and a happy Christmas and New Year to all. Seth LaK 9 - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html