Archived posting to the Leica Users Group, 2000/05/01
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]"Henning J. Wulff" wrote: > > At 1:28 AM -0700 5/1/00, Mark Rabiner wrote: > >What was it we said on that I remember something about 2 aspherical elements > >being better or worse than one but I'm not sure if the early expensive ground > >version was supposed to be better than the current pressed soft glass cheap > >version. Or not. And why. I'd search the archive but I'm not sure how on this > >particular question. Post me privately if you think this would be a skipping > >record discussion. > >Mark Rabiner > > The points made were that some Zeiss engineers had shown to their > satisfaction that more than one aspherical surface per lens was > superfluous. > > The glass in the new one is not softer (on the verrry remote chance that > you were serious....). As far as the performance is concerned, all in all > they are nearly equal, with the new one having a slight edge in some aspect > (I forget which). In any case, not to worrry about. > > * Henning J. Wulff It's my understanding that all our new generation ASPH's starting with the 24 are the result of soft glasses from Hoya which are pressed into place using a new process; a machine from a third party. Previously the high end ASPHs were ground down the whole way by one old guy who was kept very busy and they made sure he took his vitamins. Hence the extra grand or two per lens. The glass would harden after the process was over. I assume it involved heat. Mark Rabiner