Thanks. I guess my question really is... How does the manual focus work? Do you tap on the icon to toggle it on and off and then tap on the screen where you want it to focus? And if in Auto focus does it just lock in one place or does it continuously focus on the main subject, or how does it work? I've not been able to find anything in any of the hundreds of Youtube videos out there or anything. Thanks.
AF keeps everything continuously in focus. Due to the wide FOV and typical subject to camera distance, it typically just stays set at infinity focus. If you get really close to an object the AF might have to work a bit more.
As far as MF goes, I haven't' used it at all on my
EVO II 6K so not really sure. I tested it once years ago with a DJI drone and it was a slider that let you slide up and down the screen to set the focus. The DJI app at the time also had tap to focus even in MF mode or you could disable the feature. I tested it once, and never went back to MF. You have probably not found anything on it because literally no one uses it. There's way more important things to worry about in the air like battery life and obstacle avoidance.
When I first started flying drones I had planned to use MF just like I use it on the ground; to shoot brackets and panos, typically with brackets and panos you want to acquire your initial focus using AF, fine tune with MF if needed, then stay in MF while shooting the bracket or pano. But what I found with drones, since they are usually at infinity focus, and you get very limited air time due to battery constraints, its better to just keep it simple and stick to AF.
Since you already own the Nano, if you really want to know how it works then you can just test it for yourself. I would just set it up on a box indoors, take the props off for safety, and test the different focus modes since it would be close enough to the subject to see visible changes as you moved objects and focus points around.