Re: Cardish/Aspherical (2)

[Leikon35@aol.com]

 Dan - Yes, it is "coma" stemming from the fashionable soft focus
 days of Hollywood glamour photography and B&W photography.
 It didnt lend itself to well to colour film.  The variable soft-fofus
 Leitz Thambar was the epitome of SF lenses; it had a filter with
 an opaque disc in the center to cover up the center which had 
 the most correction.  We used screen mesh, ladies silk hose,
 vaseline on glass and diffusion discs to obtain this "Leica Glow"
 By producing the perfect lens without any aberrations, you will
 have taken away the "Leica Glow" and will be left with only an
 ultra-sharp photograph with no character of its own. In time, with
 computer technology and copy-cat manufacturers, this will be 
 achieved by many optical companies at a lower cost .

 ***************************************Marvin
Moss****************************
 
 In a message dated 97-08-30 13:13:18 EDT, you write:
<< Note that I am calling it spherical aberation, but I am not an optical
 engineer, it may be something else like coma, but in any case, it is there.
  Some people may like the effect, but in general it makes the lens rather
 useless at 1.4.  On the otherhand, my aspherical version of that lens
 appears much sharper and "clearer" at 1.4.  I assume that this is because
 the spherical aberation has been much better corrected in this lens.
 
 I have heard of this "use of glass not as fully corrected as the Zeiss
 glass", and perhaps it does contribute to the fabled "Leica glow", but I
 always thought that this only applied to the older Leica designs, not to
 the current M-series lenses.  In any case, as a natural skeptic, I am
 rather suspicious of all the talk of "bokeh" etc.  Next time I photograph a
 model at sunset, I will take it upon myself to bring along at least 2
 cameras, and 2 50mm lenses, and try to take pairs of images with each.
 Maybe I will circulate them among interested LUG members as a form of
 "Pepsi Challenge"
 
 Dan C.