[Leica] MTF graphs and an excuse!

[Erwin Puts <imxputs@knoware.nl>]

Hi Dominique,

I have looked at the published graphs  again (asph and TE). You are 
right! Sorry I accused you of misreading the graphs.

The TriE at 40lp/mm has 72% on axis and the asph 68%.
At 15mm we have for the TE 50 (t) and 60% (s), give or take a 
percentage point in either direction.
The asph has at 15mm  85 (t) 60 %(s)

So for the sagittal direction you have the same values. These are the 
most important. The values of the tangential lines have less impact 
on the results. So even if the numbers might suggest otherwise, the 
asph is not the clear winner. It is better than the TE at least in 
the outer zones, no doubt, but it is more of a slight difference than 
a big one.
And we may add that the 15mm position is in the far-out corners of 
the negative. This position is a bit overvalued. I would look at the 
9 to 12 mm zone for  relevant info about the practical qualities of a 
lens.


Erwin