In the episode of B&H's HDSLR Educational Series found below, Shane Hurlbut goes over what you need to know about shooting video with a still lens. He says, "What are the challenges working with a still lens? Well, there is no way to actually focus the thing. There’s no autofocus on this baby. To be able to pull this off, you’re going to need your focus puller and you’re going to need to put a ring around your focus ring so you’re able to use manual follow focus devices and/or remote follow focus devices."
Watch the full episode below or read a transcript here on Hurlbut's blog.