USB Knob Adds Remote Focus-Pulling to Canon SLRs This $400 knob proves that the SLR really is the movie camera for today’s indie filmmakers. It’s called the Okii Systems USB Follow Focus, and it does what it says, allowing you to control the focus of a Canon SLR via USB. Think of it as focus-by-wire … Continue reading USB Knob Adds Remote Focus-Pulling to Canon SLRs | Gadget Lab | Wired.com