The first sequence of comparison tests indicate the "new" Noct has a
flatter field than my old one. Might be a spurious difference between two samples and thus not relating to the AI/AIS versions as such. In terms of ultimate sharpness at f/1.2 my old Noct might be a tad more sharp on-axis, but this is really splitting straws.
However, I'm less inclined to sell it off now with these results in mind. Although the AIS lens does have a history of much use, and its external appearance bears witness to that fact, it functions perfectly optically and mechanically. I don't get lenses for them to be show-case items anyway
. Besides, the asking price for that lens was a bargain all things considered so won't hurt too much in the grander scheme of things.