Archived posting to the Leica Users Group, 2007/01/12
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Doug, With the greatest respect for the Leica APO lenses, the 300 F2.8 and the 500 F4 are just about as close to being diffraction limited as it is possible to be and still be made by humans. With the correct adapter the old FD versions are cheap and mostly usable on EOS mount cameras. (on a hot day you will not get infinity focusing) Don don.dory@gmail.com On 1/12/07, Douglas Herr <telyt@earthlink.net> wrote: > > On Jan 11, 2007, at 8:51 PM, Henning Wulff wrote: > > >> On Jan 11, 2007, at 6:23 PM, Len wrote: > >> > >>> Thanks. I have the use of it (Telyt 560/f6.8) for the weekend along > >>> with a R8 body. I > >>> still find it hard to believe a simple 2 element lens can be that > >>> good. > >> > >> I have a friend, a professor of optical physics, at the University of > >> Rochester who insists that the sharpest long focal lenses have the > >> fewest elements. The Telyt lens only covers a field of 3.5 degrees on > >> a 35mm frame, 4.5 degrees on an M8 frame. > > > > Hi Larry, > > > > I think you might have the two angles mixed. :-) > > > > But it is a very good lens. Due to this, the 560 is actually somewhat > > better, or rather of more even performance than the 400. > > > > The sharpest long focus lenses would be those of limited elements, > > such as the 3 element 800/6.3 that used the most appropriate glasses. > > The 400 and 560/6.8 Telyts used special, newly developed glasses, but > > not that exotic in today's terms. The 800 unfortunately was pretty > > much unaffordable. It certainly had better performance than the even > > much more expensive and also very complicated 1200/5.6 Canon EF. > > > >> With that narrow a field you don't need to worry about all the > >> aberrations that multiple elements are required to correct. In fact, > >> if you used a narrow band pass filter, a single element lens would be > >> almost ideal. > > > > A bit tough on colour photography, which the narrow angle achromat is > > very good at otherwise. > > > > Leica seems to be continuing the 'fewer elements' design philosophy. > Comparing Nikon and Canon 300mm f/4 lenses with the 280 f/4 APO the > APO-Telyt has the fewest elements - and the highest performance. > > Doug Herr > Birdman of Sacramento > http://www.wildlightphoto.com > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information >