It appears that when you adjust the Joystick pan/ tilt smoothing and speed on C1 or 2 that this does not apply if operating joystick control through the DJI GO app on the IPhone. ( Blue circle - Drag Focus)Can someone at DJI confirm this? I think it would be a useful addition if this was possible in a future Firmware Upgrade.

Hi, the adjustment of the Joystick pan/tilt smoothing  and speed will only apply to the joystick on the handle. About the control by the blue circle on APP, the speed depends on how far your finger is away from the starting point, which means that the speed is proportional to the movement of finger or blue circle.