After some more investigation I have found a solution that works for me, running on Android.
- Plan your flight path and flight altitude in your DD project
- Take off and ascend to the flight height that you have planed in the DD project using the DJI GO4 app
- Set the camera to vertical position
- Tap to focus
- Set the camera in MANUAL mode, and adjust the shutter speed to at least 1/200 (depending on your planed flight speed). Faster flight speed means that you may have to set the shutter speed even faster
- Adjust the ISO to get an acceptable exposure
- Unplug the micro usb cable from the phone while the drone is hoovering at the flight altitude
- Reinsert the micro usb cacble, and select DD as the app to launch
- Select your project in DD
- Under advanced settings select manual camera control in the DD project, and start the flight mission
Enjoy sharp and well exposed images.