This must be the hardest question we had to answer by starting a video with a DSLR or at least a wide sensor camera. How to ensure a good focus management during action shots ? And, guess what, there’s no good answer !

Old VS new school

Some will call it the difference between cinema and amateur productions, but technology allows us to gain so much time that it would be a shame to lose it.

In cinema, focus is managed by a tape measure and a focus responsible, which have to synchronize the camera position with a pre defined focus value. It can be set directly on camera or using a wireless follow focus. It’s maybe accurate, but in my opinion it’s too long to set when you have more than 4 scenes to shoot in the day !

Autofocus during video shooting appears some years ago, and becames more and more efficient when targeting people. My first VDSLRs were able to focus before starting the video, but not while recording, so I had to use the both techniques below (and it suited me very well !)

Manual and Hyperfocal Focus

Manual focus can be managed in two ways: a fixed focus and a fixed distance between the camera and the action, or a variable distance between camera and action, so a constant update on the focus ring. By starting video on freeski purpose, it was really easier to follow a skier and keep a constant distance than to try to pull the focus ring while skiiing. Moreover, in bright conditions, the focal number can be increased and the focus accuracy will be less important.

Talking about high focal numbers, the Hyperfocal technique consists to put the focus ring on infinite value, and then to increase the F-number to reach the distance of the action. Only very close objects can be blurred, but for a skier shot on standard/wide angle at at least 4-5 meters, a f-number between 8 to 11 will be sufficient to keep a correct focus, without any effort. I don’t use it often, but I keep it in mind !

DSLRs and autofocus

I’ve heard rumors about last Sony mirorless capbilities on video focus, but as I’m only on Canon I’ll talk only about the AI-Servo feature, and the face detection tracking.

RED and FoolControl

RED integrated autofocus just don’t work. Don’t use it !

But, fortunatelly, a french guy called Mikael Lubtchansky has created an application for RED devices which solves all the worries: Fool Control.

This little gem application applies on Red devices and uses wi-fi connection. Except all settings interesting capabilities, the focus features (which only works with Canon EF lenses) is just awesome. It works like a follow-focus, but wireless, and without any rig use. It’s getting closer of the cinema-like technique, but really easier.