Right. Just get a Canon FD 50 1.4 or Minolta 50 1.4 for $80 including adapter ($15) and the (theoretical) image quality is better than the SEL50F18. 50 1.7/1.8 old glasses are even cheaper at around $25.
(But in the end, I use SEL50F18 more because of AF and optical image stabilization. That and I’m terrible at taking photos in general.)