Lensrentals.com continues to release new MTF charts for various prime and zoom lenses. This time, they test 70-200mm f/4 lenses from Canon, Nikon and Sony. The Canon EF 70-200mm f/4L IS II USM does extremely well.
The conclusions here are pretty simple. If you shoot (or adapt) Canon EF mount lenses the Version II Canon 70-200mm f/4 IS II is excellent. It’s so good that you should only buy the 70-200mm f/2.8 version if you need f/2.8. (Since lots of people want the narrower f/2.8 depth of field for portraits or need all the light they can get for stop-motion action photography, the f/2.8 still will have lots of takers.) Check out all of the MTF charts at Lensrentals.com