No… Just no. Auto focus for DSLR motion picture was a topic raised at a discussion panel I took part in this weekend at the PhotoCine Expo. Auto focus works great for shooting stills with just about any modern camera but it just isn’t appropriate for cinema. To clarify, I think it’s a must for shooting quick and gritty, reference material or home movies. But with the shallow depth of field and artistic styling of images rendered by a RED camera or DSLRs, it just isn’t a good idea. Nikon’s new D7000 does 3D facial focus tracking by recognizing a face and keeping focus on it which is cool, but why would you want to focus on just a persons face. What if the shot calls for a long, slow focus pull between two subjects that are 20 feet apart? Okay fine, you could use software and tell the lens to pull focus from distance ‘X’ to distance ‘Y’ and specify a given focus pull rate. But now you just have a mechanical focus pull done by a computer that has no emotion or feeling. There is no organic allure or life to the scene.
To add to this proposed flaw I present exhibit B: Auto focus lenses are loose and sloppy and don’t work well for motion picture. Due to their inherent mechanical pitfalls such as loose tolerances, low quality internal components, and short focus throw, this makes auto focus lenses a poor choice for motion picture since it introduces image shift, unreliable and unrepeatable focus marks, and other inconveniences. A cinema lens uses manual focus for a good reason. It keeps the image stable when racking focus and allows the shooter to pull focus in a way that expresses the emotion or passion that a scene should be able to convey. Basically, there is no way to instill life or humanity if you assign focus to a computer. When the day comes that a computer can carry out such tasks, I’ll be locking up my vacuum and hiding in my safe room.
(REVISION) Oh and I almost forgot to mention that pulling focus is more than just a tradition. It’s a craft that many have spent a career refining. This is why there is a job on a professional movie set for a “focus puller”. It’s not just a crabby old guy who doesn’t want to change his ways or embrace a new piece of technology, Auto focus in cinema just isn’t… Cinematic.