Thanks for all of your answers guys!
I totally understand the "photography game" with shutter speed, f-stop, ISO. I'm a hobby photographer since years, so this should not be the problem
but for some reason, the sharpness is sometimes there and sometimes not, so probably the aircraft is a little bit different to DSLRs. I did the last flights everything in manual, so also the focusing. The focus threshold is switched on and shows me the things in focus, but the end result is telling sometimes a different story.
Maybe I change to AFC again and see what the results are
What I think you will find over time is that AF on the Mavic is hit and miss, at least that is what I see. Miss will not be a grossly out of focus, but instead what you may see is one side of the image may be softer than the rest.
Attempting to manually focus a Mavic drone, IMO is a waste of time unless you have a subject within 20 feet or less.
You can't zoom to 100%, and the image on any iOS device I have used is way too soft as DJI doesn't seem to respect the retina screen resolution (common issue). The image will be slightly better on a
SC or
Crystalsky, but you still really can't dial in critical focus like on a DSLR when zoomed to 100%, which is a huge oversight IMO. Currently on iOS devices even if you could zoom into 100%, the image would be so soft you really couldn't determine critical focus.
What I like to do is use the AF, hit in the center of the screen an area of the subject I am shooting, then once I get AF confirmation, switch to MF. You are still gambling on the fact that the camera got the focus correct, but by switching to MF you have locked that focus in.
Use peaking as you have mentioned, I have tried manual focus with peaking on distance subjects and it's just for me nothing like on a DSLR, so I only use it as a added tool.
I would stay away from AFC, as you always have the chance the camera will hit the sky and miss focus or a dark area of the image and again miss focus.
There are many ways that DJI could improve the MF experience for a stills shooter, but they still are mainly concerned about video and not stills.
I will also tend to reacquire my focus on after I have moved the drone to a different location, using the same method.
Luckily the AF system on the M2 Pro seems to be most often accurate for me, and I just have to deal with the fact at F4 usually one side of my image may be slightly softer than the rest, but it can be fixed in post.
Paul C