This follow focus is simply excellent, and this at an unbeatable price! Indeed it is very convenient, allows fluid to make its focus manuals and avoid jittering, short, everything a videographer research to improve the focus of its videos! I use it now for several weeks on a Nikkor 35mm f / 1.8 (mounted on a Nikon D3200) and no complaints so far. The only downside I found using it on a Canon lens 18-135 is that it "fell" when it let go (due to its weight and the low resistance of the focus ring target), which had the effect of completely disrupt the focus ...
Very good follow focus, therefore, but to avoid on the wealthy objectives focus rings with little resistance.