Bill, You are welcome!
Originally Posted by Bill Burk
I don't see SLR lens designers fooling themselves that something could be improved (at a reasonable cost) in SLR wides. Probably most users are totally cool with distortion even in 50mm. After all, its not big deal if You shoot cats.
Nikon and the rest did their best and with current photo manipulation techniques, distortion is just "one of those things" to be taken care of.
The Zeiss Sonnar "look" is probably a menu item in some software by now.
IMHO, no RF lens improvements appeared in the recent decades.. the firm base was reached in the 50's.
If You print optically from film and You shoot RF LTM (or M39), then using the same camera lens on Your enlarger might be revealing.