Actually I think that at present the correct keys are:
- Increase Drone Translation Speed: F6
- Decrease Drone Translation Speed: F5
- Increase Drone Rotation Speed: F8
- Decrease Drone Rotation Speed: F7
F1 and F2 are for the depth of field.
***Note:
Probably during the development phases/updates there have been some changes to the default keys for the Drone camera, because I too had problems with the keys by reading old guides.