Auto focus, C1 setting to: video recording, extended tele convert on, Full HD 50P,
Here by hand.:
First full frame rate, -then the same fottage in 25% speed, and to the end; the take off in 10% speed.
Edit; FCPX 2.2
Credit to the GX8 and the new way of video settings in the C1 camera functions.
ProRes 422 FHD 50P file there download