SMALLRIG 360 ° Rotation Seamless focus Gear Ring Φ72-Φ74mm for Follow Focus, Compatible With DSLR Camera Video Cameras - 3293

This particular product serves such a specific task there aren't a great many degrees of freedom for it to excel or fail at, hence my (rare) full rating.This fits my Sigma 18-35mm Art lens perfectly. Note that the barrel diameter for the lens is 78mm, right at the low end of the ring's range of diameters. There is some stretch/give in the rubber so I imagine it will be comfortably snug for 80mm diameters (but I cannot test this).Rubber seems durable, but I haven't gone out of my way to stretch this.More importantly, it was an immediate, and large, improvement over the adjustable strap that comes with the mini follow focus. I had problems with getting a tight fit (I may have been over-cautious in how tight I pulled it) - and there never seemed enough track to satisfy the full throw of my Sigma lens. This does away with all of that. Moreover, the follow focus gear meshes with this ring far more effectively than with the adjustable strap (which is considerably narrower and, perhaps, with ill-fitting 'teeth').I would certainly consider getting additional ones for any other lenses I might use my follow focus on in the future.

Perfect

Good quality rubber