Lensrentals: System MTF comparison, Canon vs Nikon

I indeed think goosel is right. My 28/1.8 clearly shows the mid-frame slight softness with the D800, even at f/8. The areas used by photozone for "Border" and "Extreme" are actually pretty close: http://www.photozone.de/lens-test-faq

Of course there can be copy variation and some lenses (the one from anothermike) have a less pronounced "doughnut" effect. There could also be tradeoffs, of course. My lens has a detectable doughnut effect but it is just amazingly sharp at the full frame edges and even extreme corners. Perhaps anothermike's lens will not be quite as good there...?