Archived posting to the Leica Users Group, 2008/01/06
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]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 G?nter 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 >