How to autofocus in video

[redcrit]

Hey,

It's been one year I've been using Magic Lantern, and I never found out how to autofocus when I'm in movie mode. When I press the shutter button, it just shows me on the screen the framerate and a bunch of other informations, how can I make it it to focus to the point I want to please ?

Thank you

[markodarko]

Manually focus. Autofocus is not your friend when recording video. :-)

[dmilligan]

You didn't mention what camera. Some cameras have AF in movie mode capability built-in. These cameras have special phase-detect pixels for this purpose. The normal AF sensors are blocked by the mirror when the camera is in LV or movie mode, therefore if you don't have special phase-detect pixels in the sensor, you must rely on contrast-based autofocus, which is a guessing game (therefore slow and unreliable). AFAIK, nobody was able to come up with a contrast-based method that was actually usable (there were some attempts: http://www.magiclantern.fm/forum/index.php?topic=1492.msg3724#msg3724 and http://www.magiclantern.fm/forum/index.php?topic=1396.msg3539#msg3539).

Manually focus. Autofocus is not your friend when recording video. :-)

That's not always true for all types of situations or environments, and current tech has gotten pretty good/sophisticated.

[markodarko]

That's not always true for all types of situations or environments, and current tech has gotten pretty good/sophisticated.

Oh absolutely, you're right of course, if you're doing an interview or some shot where you have one subject in the frame and don't need to pull focus then perhaps AF would be useful there.

But I guess it comes down to whether you want to be in control of the focusing or not. No AF is perfect - on any camera.

[redcrit]

Oh thank you, I get it I was talking about a 5D mark II