"I have the same frame with 4016 380Kv motors. 16 Amp Bat. Pixhawk. 
Some issues :  
RC_FEEL_RP = 50 is overpower, try 45-48
PID: After auto tuning the multi is very responsive, lower P value will make it smoother. 
Take off: "smoothly and…"

"Hi hugues i have some problems with your circuit. What is the usb pinout connection ?. Shutter and focus goes to V+?"

"@Darius Jack Google Maps and Google Earth is for all kind of public.They don't need HR-image so Why spend money and resources in that?. 
"Commercial sat imaginery is ok for public administration, public funded grants, large corporations, not exactly…"

"@Darius Jack, You'r right, In any case it was only an example. There are others very high resolution sensors: WorldView, WorldView-1, GeoEye-1, WorldView-2 y WorldView-3."

"Survey "23 Km2 3-4 times in a 8 months" with UAV it's possible but the cost/benefit is huge, because the post-processing data of 23 km2 is not easy. Also you need take in account flight time, weather conditions, cpu time consumption, fails, etc. 
In…"

"The big problem is try to answer: "What is the economic benefit?". If we are capable to answer this question with a number perhaps we could have a business opportunity. Only Airinov (Sensefly) try to answer this question, but only for two culture…"

"I have the same problem, I don't find the solution. "

"A fuse amperage?"