Comment by tecleandor

And just mentioning for people unfamiliar with this stuff, that's not a camera and not even an accessory for a camera. That's an accessory for an accessory. :D

It's a LiDAR that follows a subject and gets distance measurements, and then sends them to an additional accessory which is typically used to control focus in cinema cameras. That second accessory has a motor and is attached to a cinema lens that has certain threading or grooves where the accessory can grip and change the focus.

In cinema, the camera operator (usually) only moves the camera, but not the focus. For that, there's a 'focus puller'. A person who finely operates the focus, sometimes at a certain distance, using some sort of specialized control.