Hi folks!

Almost everybody who got into comparing LF lenses or even own testing knows the large format lens test of Perez / Thalmann ( http://www.hevanet.com/cperez/testing.html ).

The values at f/22 for the best lenses for instance a Symmar-S 150 f/5.6 mm are about 60 lpm or slightly higher than 60 lpm. In the case of the Symmar even 67 lpm.

For the theoretically maximum resolution of a perfect lens at f/22 I find 75 lpm (diffraction limit). Tmax 100, the film Perez / Thalmann used for their test, should resolve a maximum of 200 lpm at high contrast (1:1000).

If I calculate the maximum system´s resolution for that with 1/max system resolution = 1/max resolution film + 1/max resolution lens at f/22. This is the result I find:

max system resolution = 1 /(1/max resolution film + 1/max resolution lens)=1/(1/200+1/75)=54,5 lpm

This theoretical value of about 55 lpm is below the often seen values of 60 lpm or even slightly higher for different (very best) lenses at f/22 that were observed in the testing.

Any thoughts to this "paradox"?

Best regards,
Andreas