Hallo Uwe,
die Kurve für den Farblängsfehler des 115mm f/7 verläuft so, daß sie
die Apo-Defonition von Abbe nicht erfüllt (und auch nicht die von H.Rutten):
http://geogdata.csun.edu/~voltaire/tmb/definition.html
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">Zitat:<hr height="1" noshade id="quote">Abbe's definition of apochromatism was the following. Apochromat: an objective corrected parfocally for three widely spaced wavelengths and corrected for spherical aberration and coma for two widely separated wavelengths.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Die Definition von T.M.Back aber doch:
<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">Zitat:<hr height="1" noshade id="quote">After designing, testing and selling many different apochromatic lenses I can state this: There is no "definite" line where a lens becomes "apochromatic" in the world of commercial apochromatic lenses.
But any lens, be it a doublet, triplet, quad, air-spaced or Petzval, that has a peak visual null (~5550A - the green-yellow) with a Strehl ratio of .95 or better, coma corrected and is diffraction limited from C (red) to F (blue) with 1/4 wave OPD spherical or better, has good control of the violet g wavelength with no more than 1/2 wave OPD P-V spherical and optical spot sizes that concentrate the maximum amount of photons within the diffraction limit -- a result of the low spherical aberration, which can be seen with modern optical design programs, as the "spot rays" will be seen concentrated in the center of the spot, not evenly or worse, concentrated outside the center -- will satisfy the modern definition of "Apochromatism."
Lenses of this quality do not satisfy the Abbe definition, but for all intents and purposes, will be color free and will give extremely sharp and contrasty images.
Thomas M. Back
TMB Optical <hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">
Es scheint also eine Definitionsfragezu sein. Die Kurve des 130/1200mm LZOS
verläuft dagegen "klassich", wie man es für einen extrem guten Apo erwarten würde.
MfG,Karsten
Edit:
Halt, bei F (486nm) fällt der Strehl des 115mm f/7 schon etwas zu niedrig aus
um die Definition von Back zu schaffen.
Wie auch immer, ich vermute daß das Objektiv noch etws besser justiert/
zentriert werden kann und die Definition von Back dann doch schafft.
