[Leica] noct performance

[Erwin Puts <imxputs@knoware.nl>]

>If the experts say that a Noctilux is not quite
>at its best when wide open compared to when it is stopped down a 
>bit, I guess I
can take their word for it, but I seriously doubt that I'd notice it 
in my work.

Any critical user will see a quite remarkable difference in Noct 
pictures taken at full aperture an stopped down to let us say f4. The 
contrast is visibly higher and the rendition of very fine detail has 
also crispened a lot and it there for anyone to see.

  It has also been noted that "the Noctilux does improve when stopped 
down (about 25-30% better resolution").
Well the message does not specify art what aperture and at what part 
of the image this performance is proposed to  occur. Anyway it is not 
correct.
At f1 the Noct has a contrast for the 40lp of 30% in the center and 
10% on a location 6mm from the axis. At f8 the contrast for the same 
40lp is 70% for both locations. An improvement of 100%. The other way 
around: at f/1 the Noct resolves 30 lp with good contrast and at f8 
has a resolving power of above 70 lp. Again a 100% improvement


Erwin