Originally Posted by JohnG
...the new sigma 35mm 1.4 - THAT looks like an exceptional lens (assuming no focus issues which seems to be an issue on Canon 5dIII and 1dx cameras).
If I understand it correctly you can micro-focus the Sigma @ 4 different ranges setting instead of just 1 allowed by the body:
-> It get even better with the 120-300 f/2.8 as you can further micro-focus its zoom settings @ 4 different focal ranges!!!