I just got a hands-on Panasonic GH5.
I recorded in camera at UHD 3840 x 2160 25P, 10bit 4:2:2 h.264 150mbps.
The Firmware version was 1.0.
I had found that V-log L was powerful enough for normal shoot.
Camera : Panasonic GH5 Firmware Version 1.0
Lens : Leica 12mm F1.4
Edited : DaVinci Resolve 12.5.5
Color Graded : DaVinci Resolve 12.5.5
Exported at UHD resolution.