Okay, I'm confused and need advice. My camera is the Arri SR2 (converted to Super). My lens is the Cooke Varokinetal 10.4-52mm T2. These lens were made for Super 16. My camera came with a follow focus. See photos. The camera tech informed me several years ago that my ff will not work with my lens. Is that ff for a certain type lens? Why doesn't it work for my lens? I will be using that same camera and lens. I need a ff. What ff can I get and it will work?