[Leica] 50mm -- the nearest to ASPH is Noctilux

[Denice Martone <denice.martone@nyu.edu>]

Thanks to everyone for helping me think about 50mm -- the nearest 
ASPH is Noctilux so upon someone's suggestion I went to Erwin Puts 
http://www.imx.nl/photosite/leica/mseries/testm/M10-50.html
who has a lot to say! Here's some of what struck me:

"When comparing Velvia transparencies taken with the Summicron-M 50mm 
and the Noctilux in an
   identical setup (some strong lightrays leaking from the edge of a 
wall) the Summicron (itself famous for its flare
   suppression capabilities) showed reflections in the center of the 
picture where the Noctilux was absolutely free of it."
"Overall contrast at full aperture is lower than that of the Summilux 
and at f/1,4 the Noctilux is still somewhat behind this
   lens. When stopping down to f/2,0 we can compare the contrast of 
all three 50mm lenses, Noctilux-M, Summilux-M and
   Summicron-M. The Summicron-M is best, but the Summilux is very 
close as to be indistinguisable is most picture taking
   situations. The Noctilux has a slightly lower contrast."
"We compared the Noctilux and the Summicron at a distance
   of 1meter at all apertures. The Noctilux showed sharp 
object-outlines, but fine details were a little fuzzy at the edges
   and very fine detail was not resolved at all. From f/4,0 till 
f/11,0 the performance of the Noctilux markedly improved and
   became excellent at f/8,0."
"Closeups at full aperture, however, are not the Noctilux's forte. 
But then who will use this lens in such a situation. The
   depth of field at f/1,0 and 1 meter is a mere 1-2 cm! Portraits at 
this distance and aperture are bound to disappoint from
   a technical perspective that is."