Lumix G9: Any solution to video CAF problems?

Started 10 months ago | Questions thread
OP Kawika Nui Contributing Member • Posts: 834
Re: G9 Video C-AF ISO 10,000 w/ P-L 12-35

Pete Berry wrote:

Kawika Nui wrote:

Kawika Nui wrote:

Recently got a G9 and have been playing with it to get used to it and see how it performs.

I was surprised and disappointed to find major deficiencies with the video CAF (shooting mp4, 1080/60p). In a very simple shooting environment, the camera kept defocusing and refocusing for no reason. There is almost no movement toward or away from the camera, and the distance is close to infinity anyway. The video starts in focus, then arbitrarily moves out of focus and back a couple of times - all in a very short time.

Does anyone have a suggestion for fixing this?

I seem to have solved the problem.

Set AF lever to AFS (Single).

Set Video AF to Continuous AF Off

Set Eye Sensor AF to On.

I'm an EVF shooter, so this works perfectly. Ended the problem.

G9 C-AF w/ C-AF on in menu and AF lever - 12-35/2.8-v1 @ 35mm f/2.8, 1/30, ISO 10,000, shooting 4K 60p. Rendered in 4K 30p (not slow-mo). The range about 2-20', but works very well in this very low-light situation. Used a mod large single area focus box - about 2/3 frame height. Panning around my cluttered studio

Yes, the CAF works quite well for situations involving changing distances between camera and subject.  However, my original post dealt with something quite different: the G9's habit of arbitrary and random de-focusing and refocusing while shooting a subject where there is little or no change of distance between camera and subject.

lit by three much-dimmed ceiling spots, with corners barely visible. Auto WB (very good in G9) couldn't reach this very low color temp.

I thought the video IQ was pretty amazing with fine-grained noise and no macro-blocking at all in shadows - the usual curse of hi-ISO video - with very good color and lack of detail smearing which I wasn't expecting. In darkest areas able to reach a true 0,0,0 RGB black, which is the key to good color, and is generally over-run with noise by way short of this ISO.

And a couple of frame captures...

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