Via Philip Bloom comes the handy tip to send in Nikon ZF lenses to Duclos Lenses and have them "cinemodded." What is the cinemod process? From the guide: Duclos de-clicks your iris ring (giving you stopless control over exposure), adds a physical gear for follow focus use, and adds a common-size front ring (for example, if you have a 77mm Fader ND, you can have all of your lenses fit with 77mm front threads). Note that the problem with sending in Zeiss ZF lenses is that Nikon lenses pull focus in the opposite direction of all other brands, so for that reason alone I have a distaste for them (pulling focus on Nikon lenses and then switching to any other brand is a pain in the ass in terms of muscle memory). So while Bloom may recommend sending in ZF lenses -- which is a great option (and I should note that some follow focuses (focusi?) allow you to reverse their gearing to correct this problem) -- Duclos can cinemod many different still lenses. I sent them an email about converting different brands and got a prompt response, which can you find on the DSLR Guide's Lenses: Converting, Renting page.