f/1.4 vs. f/1.8

[Vince.1551]

F1.4 is an overkill

 

[STM]

The difference between f/1.8 and f/1.4 is a half an f/ stop. In most instances, that difference is negligible. If money is an object, I would go with the f/1.8

 

[2WheelPhoto]

The f1.8 is a newer aspherical design which makes it sharper with better contrast than the 1.4 at wide apertures which is basically unchanged in optical design for 40 years (they improved lens coating that's about it).

Wow nice, can you please link to a comparison of the two?