Patrick Fee

Thanks for the info.

In theory it shouldn't but since he's talking about a strap with gear teeth on it instead of a continuously geared surface it does. The teeth shape stays the same but the valleys between them is different depending on the diameter of the lens it's wrapped around. It may not be a whole lot but consider the difference between laying the strap completely flat vs wrapping it around something the size of a quarter. The distance between the teeth stretches out the smaller you go.

I agree with with Kyryll. I used to work for Zacuto and I know their follow focus will pull in toward the lens gear when you tighten it down. Try to leave like a half mm or so and watch the gap between the gears close when you tighten everything down. The strap type of gear could be a problem too if its cheap and bumpy. Also, the pitch (distance between the peaks) will change slightly depending on what diameter the lens barrel is and could lead to some engagement issues.

I actually just started working on a new design for a softbox speedring and we're planning on having it somewhat modular to work with different fixtures, stobes and constant lights. Out of curiosity, what diameter ring would you need to fit the DeSisti light you mentioned?

The one on the right looks like a traditional cine pitch (0.8) the others are probably the pitch to work with either older B4 mount Fuji or Canon lenses.