I need an autofocus 50mm prime. 

I have a Nikkor 50mm f/1.2 that I can (and do) mount to my EOS bodies, but it’s a manual focus. There’s times when I need AF (motorsports, kids, animals, photographing a nude model after midnight in a police department’s semi-darkened fleet garage…, weddings…).

The EF 28-135mm f/3.5-5.6 IS USM is my least favorite lens. I have it. I am loathe to use it.