Questions about GH2 autofocus modes

[noam]

I've been shooting with my GH2 for about a month now, but it wasn't until yesterday that I decided to try using autofocus while recording video. I turned continuous AF on and played around with using afc/afs and the autofocus settings (tracking, etc.)..

I realized through the process that I am not familiar enough with the different settings and their applications, and was hoping people could make a suggestion for my intended usage of the autofocus feature..

I rarely will use autofocus, as much of what I shoot is narrative and commercial work. However I do have a shoot coming up where I will need to have my GH2 on a shoulder mount and walk behind two people, following them walking down the street. Which setting(s) would you recommend for maintaining the best focus under those conditions?

 

[mpgxsvcd]

My suggestion is shoot as wide as possible(14mm F2.5 works well for AFC) and use the ETC feature if you need to tighten the frame. The AFC is good on the GH2 with the 14mm and 14-140mm lenses near their wider end. However, as you zoom in or get too close to the subject your depth of field will get too shallow and it will hunt for a subject to focus on.

Make sure you are actually setting it to auto focus. The little Auto Focus dial on the top left of the camera does nothing for auto focus in video. That dial applies to stills only. There is a menu option in the video section that turns "Continuous Auto Focus" on or off for video. Set that to on and then it will Continuously auto focus in video for any m4/3s lens that supports this feature. The only m4/3s I am aware of that does not support AFC for video is the 25mm F0.95 lens. Even the 20mm will do AFC during video. It will be VERY SLOW though.

Here is a sample of the 20mm doing AFC in video at a very close range(Not Recommended).

http://www.youtube.com/watch?v=1efPFdu8CU8

 

[noam]

Thanks for your response.. That definitely clears up a lot of my questions.. and it's great to know the 20mm will be slow, because that's the next lens I will be purchasing!