Took this lens out for a backyard spin, do not get me wrong, I am posting my hillside because it is the prettiest now than it has ever been and summer will not be kind to it, be so as well, only have to weed once a year. I will compensate you with pics of the Japanese and Chinese gardens at the Huntington Library with the other 18mm, the 3.5.
Common to all the real wide old Nikkors, the near corners can be had real sharp when properly focused, the far corners almost never.