All you have to do is compare a recent 50mm f/1.4 lens such as the Sigma Art or Sony GM to an older design before the advent of computer-aided optimization (eg

All you have to do is compare a recent 50mm f/1.4 lens such as the Sigma Art or Sony GM to an older design before the advent of computer-aided optimization (eg the Canon EF 50/1.4). The new designs are very contrasty and sharp wide open, almost across the frame. The older designs need to be stopped down to achieve critical sharpness, and suffer in the corners. Just so much progress in the past 15 years.