When you shot a video while walking on a street, do you use AFC or AFS?
Does it make any difference AFC/AFS in a such case?

Hi DJIDream, we do appreciate you interest in our products. AFS is good for photographing subjects that don’t move, such as a stationary object or posed gesture; AFC is good use when photographing for moving objects. The camera will keep re-focusing as the object moves. For AFS, you need to tap the screen to focus. It is suitable for manually changing focus from a distant object to a close object and vice versa. For AFC, when shooting a distant object or a close object, the camera will automatically focus. The settings in the GUI and DJI Mimo app are synchronized.

If you mean shooting the scene in front of me then I prefer AFS. It does seem to refocus on its own which is a bit weird but suppresses the focus breathing better than some people have moaned about and defocuses a bit less while panning.  
Others may have a different experience though.

Thank you, I appreciate your answers.
What is the signification of the yellow square that randomly shown on the screen during filming on AFC mode? This sign can be shut off?

DJDream Posted at 3-22 10:33
Thank you, I appreciate your answers.
What is the signification of the yellow square that randomly shown on the screen during filming on AFC mode? This sign can be shut off?

Square box in top left or [ ] brackets?

Ray-CubeAce Posted at 3-22 15:50
Square box in top left or [ ] brackets?

I mean [ ] brackets, generally shown in the middle of the  display from time to time.
Does it mean that the camera is focusing when this yellow sign shows?

DJDream Posted at 3-23 01:10
I mean [ ] brackets, generally shown in the middle of the  display from time to time.
Does it mean that the camera is focusing when this yellow sign shows?

I think it's showing the main focus area when you have moved away from your original targeted area but don't quote me on that. Normally an area in focus comes up green. The manual could be more helpful than it is.

how to format

For street videos I would definitely use AFS, but use the touch to adjust focus on the fly when I need to. Especially if there is a lot of action around (people walking past etc.) AFC might get stuck on something irrelevant pulling the rest of the video out of focus...

DJI Paladin Posted at 3-22 10:15
Hi DJIDream, we do appreciate you interest in our products. AFS is good for photographing subjects that don’t move, such as a stationary object or posed gesture; AFC is good use when photographing for moving objects. The camera will keep re-focusing as the object moves. For AFS, you need to tap the screen to focus. It is suitable for manually changing focus from a distant object to a close object and vice versa. For AFC, when shooting a distant object or a close object, the camera will automatically focus. The settings in the GUI and DJI Mimo app are synchronized.

Thanks you for useful advice!

Lysak2003 Posted at 12-4 06:16
Thanks you for useful advice!

You are more than welcome. If you have any other concern or inquiry. Please feel free to post it at DJI Forum. We are here to help and thank you for your valued support.

take a look at my video that discusses this and more - it's only 4 minutes

https://youtu.be/EVW1RhXr66o

duplicate post - can't remove so edited.

AFS if standing still (not changing the distance between the lens and what is being filmed) since AFC changes focus once in a while at the moment, lets hope there is a new update on Osmo pocket´s software.

Ray-CubeAce Posted at 2019-3-23 05:10
I think it's showing the main focus area when you have moved away from your original targeted area but don't quote me on that. Normally an area in focus comes up green. The manual could be more helpful than it is.

The green box is tracking.
The yellow box that comes up is Continuous AFC  focus taking a reading

Is AFC or AFS best for drone photogrametry? I’ve heard some pros use AFC because it auto focuses every shot taken…?

If you want to keep the focus constantly on certain distance until tapping on the screen to focus, use AFS. If you instead want the camera focus automatically to the subject that comes into the picture the closest to the camera, choose AFC.