OI Photography said:
That's because the NAZA compensates to keep it level for you. Try that same thing in Manual mode and you'll see the difference. The left stick is definitely throttle, but like any control input in GPS mode it's more like "intelligent assisted throttle"
Technically,
all of the controls are throttle, because they are all translated to relative motor speeds.
And there's nothing manual about "manual" mode--it's just a fly-by-wire mode with somewhat less computation thrown in than other modes. A truly manual mode would give you four throttle levers, one for each motor, and would be pretty impossible to fly.
In old-school airplane RC the left stick really was throttle--the receive channel drove a servo connected to the single engine, and in helos it is presumably collective pitch (which also is not throttle).
Functionally the left stick is more of a "go up/down" control; in manual mode "up" is defined as "away from the landing gear" whereas in the other modes it is relative to the earth.