Cube FPV

Setup Steps

Throttle Scaling and Mid Point

The final part to getting great cinematic footage is altitude hold – being able to fly straight and level without losing or gaining altitude. To do this you will need to use throttle scaling and expo. Throttle scaling increases the resolution of the throttle while throttle expo will make the throttle more docile around the hover point.

Betaflight OSD Setup

In Betaflight on the OSD Tab enable the throttle icon and place it somewhere visible on the screen. We will use this to make a note of the throttle position where the drone takes off. 

Throttle Scaling

Now with the throttle value visible in your goggles, test and note at what throttle percentage the drone takes off. If this is below 50% go into Betaflight and do throttle scaling and reduce the throttle limit by 10%. Test again and reduce more and repeat this process till you attain liftoff at 50% throttle.

Throttle Expo

Finally we look at throttle expo. This gives a degree of softness around the throttle mid point and this allows you to more precisely target the correct throttle value to maintain level flight. 
Assuming you have set your throttle scaling to take off at 50%, now go into Betaflight and set the Throttle Mid to 0.5 (50%) and the Expo to 0.4 or 0.5.