Archived posting to the Leica Users Group, 1997/07/02
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]On Wed, 2 Jul 1997, Kari Eloranta wrote: > > Martin Tai wrote: > > >On the contrary, the only way to get best optical performance > >is UNIT FOCUSING, ie, move the lens as a whole. The internal focusing > > I'm quite sure this is false. For example macros are specialized > designs for short distances that can be outperformed at infinity. > And obviously viceversa. Macros don't exist only because some people > like to get real close, like two inches. Their imageplane flatness etc. > characteristics etc. are already superior at half a meter which is > within the distance scale of a SLR normal lens. If your argument would > be true, a good, fixed, optical formula would work uniformly well at > all distances (that the lens focuses) which is not true. > > I'm not saying that the Contax design is bad, not at all. In particular > it allows the user to switch off the AF and do the focusing manually > with floating elements AND with a tight lens. But to me it seems that > this type of AF in actual use sacrifices some of the optical potential > of the lens. > > Regards, > > Kari Eloranta > > Wrong ! None of Leica's macro lenses, Macro-Elmarit 60/2.8, APO-MACRO-ELMARIT 100/2.8 Macro-Elmarit-R 100/4 use floating element design at all. Variable spacing focusing ( internal focusing ) is widely used in Japanese designs, not favoured by Leica martin tai