I found an Ernst Leitz Canada ELCAN paper on Leitz Summicron 35mm and interestingly there are highest amount of aberrations before and after the stop .
I am talking about two lens elements.

Highest aberration was Spherical Aberration 3.

Let me introduce the strangers to computer image correction world. For last 10 years , there is a increasing amount of papers discusses the image correction.
And after 2010 , there is a trend to put a single element or very poor quality lens which has so much aberrations but MOSTLY SA3.

They say if there is spherical aberration very strongly presented in lens , its very good thing to correct everything to unlimited amounts compared to lenses.

They say , if there is SA at a lens , correction error becomes too low to afraid and you can deblur limitless.

I found that Leitz lenses are small diameter , their glasses %20 higher refractive index but their resolution is 4 times of average lens.

I thought , they use SA3 before the stop and after the stop , they deblur limitless to make resolution fly.

May be I am wrong.

What do you think ?

Mustafa Umut Sarac
Istanbul