Hi, 
  
I've got pretty nice lenses for my 5D Mark III. 
Sigma 12-24mm f/4.5-5.6 EX DG 
Canon 24-70mm f/2.8 USM 
Canon 70-200mm f/2.8 USM 
  
Since those lenses are made for fast autofocus operation for photography, the distance from the nearest focus point to infinity on the focus ring is quite short. This should make it harder to pull focus smoothly. 
Here is a short explaination: