Archived posting to the Leica Users Group, 2008/01/06
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]There is no Apo glass, the different glasses such as ED, FL etc. have Apochromatic properties. When Leica uses these glasses, they attach the Apo prefix to the lens nomenclature, such as the 180/3.4 Apo Telyt, 280/2.8 Apo Telyt etc. Gene -------------- Original message ---------------------- From: "Fred Hess / Phenix Visuals NL" <fredhess@phenix-visuals.nl> > > Hello, > > There is not something like 'apochromatic' glass. Only apochromatic > lensdesigns, > These APO-lensdesigns show no, or almost none, chromatic aberrations. > > If you would like to know more about lensdesign and lensaberrations take a > look in the book of Graham Saxby: The Science of Imaging ISBN > 0-7503-0734-x > > Kind regards > > Fred Hess. > > ----- Original Message ----- > From: "Raimo K" <raimo.m.korhonen@uusikaupunki.fi> > To: "Leica Users Group" <lug@leica-users.org> > Sent: Sunday, January 06, 2008 9:15 AM > Subject: Re: [Leica] The Tele elmarit 135 Is So A Real Pooch of a Lens > > > > I find it hard to believe. > > Leitz/Leica have used special glasses for a very long time but as they > know > > glasses and also what apochromatic lens design is they have never used > > the > > term apochromatic or APO glass. > > For example in Günter Osterloh´s book Angewandte Leica-Technik there > > is a > > very thorough description of Apo-Telyt-R 1:3.4/180 mm lens, with > discussion > > of different types of glass like anomal dispersion, calcium fluorite, > > lithium fluorite etc. but no mention about APO glass - the lens is "ein > > ausgezeichnet korrigiertes, apochromatisches system". As is well known, > > Osterloh worked in Leica marketing. > > All the best! > > Raimo K > > Personal photography homepage at: > > http://www.uusikaupunki.fi/~raikorho > > > > > > ----- Original Message ----- > > From: <wildlightphoto@earthlink.net> > > To: "Leica Users Group" <lug@leica-users.org> > > Sent: Saturday, January 05, 2008 8:15 PM > > Subject: Re: [Leica] The Tele elmarit 135 Is So A Real Pooch of a Lens > > > > > > > Raimo K <raimo.m.korhonen@uusikaupunki.fi> > > > > > >>Since when do they use this designation? > > > > > > Since 1984 at least if not earlier. > > > > > > Doug Herr > > > Sacramento > > > http://www.wildlightphoto.com > > > > > >> > > >>----- Original Message ----- > > >>From: <wildlightphoto@earthlink.net> > > >>To: "Leica Users Group" <lug@leica-users.org> > > >>Sent: Saturday, January 05, 2008 3:17 PM > > >>Subject: Re: [Leica] The Tele elmarit 135 Is So A Real Pooch of a Lens > > >> > > >> > > >>> Raimo K <raimo.m.korhonen@uusikaupunki.fi> wrote: > > >>> > > >>>>APO means apochromatic correction of the lens, there are no > apochromatic > > >>>>elements. > > >>> > > >>> In Leica's case, APO is the designation they use for the extra-low > > >>> dispersion glass which their optical designers feel is essential to > > >>> designing lenses with apochromatic performance. This is like Nikon's > > >>> use > > >>> of the ED designation for their extra-low dispersion glass. Raimo is > > >>> correct that there are no apochromatic elements, but there is APO > glass > > >>> which is used to design apochromatic lenses. > > >>> > > >>> > > >>> > > >>> Doug Herr > > >>> Sacramento > > >>> http://www.wildlightphoto.com > > >>> > > >>> > > >>> > > >>> _______________________________________________ > > >>> 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 > > > > > > > > > _______________________________________________ > > > 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 > > > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information