[Leica] Outer zones and performance

[krieger at usc.edu (Martin Krieger)]

What matters is the performance in the outer zones, for me at least. It is 
not too hard to make a lens that performs wonderfully in the center. What I 
am concerned about is uniform performance, that is fine performance not only 
in the center but also in the outer zones, near the edges and the corners. 
Why? Like a spy photographer or in suveillance, I am often concerned with 
features of the image that happen to be in the edges or corners of the 
negatives. Hence I am quite willing to give up perhaps 5-10% of the MTF in 
the center zone for superior more uniform performance (at say 10-40 lp/mm). 
That is what Zeiss 
advertises, for example. They figure, as well, that film flatness is not so 
good that 
improvements in the center are as important and seeable as improvements in 
the outer zones. Does anyone know who makes the best performing lenses over 
all the negative? Zeiss would claim to.
Martin Krieger