Can someone please help me with "Gain & Expo tuning settings". (What does "expo" stand for?)
I understand the brake sensitivity settings and have set to 70% for smoothest operation shooting video in P-GPS mode.
What does the Sensitivity "Attitude" affect? (20%-100%)


Also,
What does the 80% - 120% "Basic Gain" range control for "Pitch, Roll, Yaw, Vertical" do?


Thanks in advance,
GDS

this should help  

The standard exp setting is a straight line : 10% stick input result in 10% power applied to the quad.
You can change the exp in 2 ways : positive or negative.
With a negative setting, if you give 10% stick input, there is only 5% applied to the quad, if you give 30% there is 20% applied to the quad (these are not real values, this is just to explain). The curve is exponential, so 0=0 and 100=100. Whatever exp value you choose, full stick gives full power to the quad (if all gain values are 100).
RC Heli/plane acrobatic flyers usually have a positive exp setting on all axes in order to have very fast response with less stick input.
The P3 being a flying camera, in my point of view it is better to have a negative exp.
The gain is a way to limit the speed (vertical, horizontal, lateral and rotational). I set the yaw gain to 80 so even if I'm full stick while panning, the quad is limited to 80% of its max yaw speed.
All these setting allow you to have smooth video.