Archived posting to the Leica Users Group, 2005/02/11
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Frank, I think you're making the assumption (as I have) that "APO" and "apochromatic" are interchangable and mean exactly the same thing. In this case "APO" is a marketing designation, like "ED" is for Nikon lenses. It looks like it's an abbreviation for "apochromatic" and the "APO" terminology was probably chosen to make us think that, but I think we'll all comprehend this better if we think of "APO" as Leica's way of saying "ED". Doug Herr Birdman of Sacramento http://www.wildlightphoto.com -----Original Message----- From: Frank Dernie <Frank.Dernie@btinternet.com> Sent: Feb 11, 2005 1:00 PM To: Leica Users Group <lug@leica-users.org> Subject: Re: [Leica] Re: Re: FS: Leitz/Leica 350mm f/4.8 Telyt-R Please point me in the direction of some explanation of what "APO" glass is then, if you know a url. I have heard of APO as an overall complete lens design specification many times but I have no knowledge that there is a particular APO glass. Frank On 11 Feb, 2005, at 16:07, JCB wrote: > I heard it from the mouth of Leitz, at Photokina, the year it was > introduced. > > JB > > > At 12:26 AM 2/11/2005, Frank Dernie wrote: > > >> AFAIK there is no such thing as "APO glass". To get APO performance a >> combination of elements of differing characteristics and curvature is >> required to cancel the fact that different colours diffract >> differently. The unusual partial dispersion glasses which this >> requires in at least one element are very expensive. Whether the 350 >> actually has these is debatable. The fact that it is v. sharp is well >> documented >> Frank >> >> >> On 11 Feb, 2005, at 01:30, SEUNG MIN LEE wrote: >> >> I have never heard that it had APO glass > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > _______________________________________________ Leica Users Group. See http://leica-users.org/mailman/listinfo/lug for more information