Hello !
I cant' find a post where to find those informations... I'm wondering about the best 4K settings for GH4 camera on zenmuse Z15 with 12mm lense.
Aperture ?
shutter speed ?
ISO ?
AVCHD/MP4/MP4(LPCM)/MOV ?
ND filter or not ?

Thank you very much for your help !

The GH4 is not a point and shoot camera.  You need to understand each function and what it does.  Aperture, Sutter Speed, ISO depends on the conditions.  I use MOV and a ND filter to keep the camera in a ISO between 200-400.  The value of the filter depends on the conditions.

Thank you for this answer.

ISO 200
shutter speed mode - 1/200 shutter speed  
(In shutter speed mode, u cannot fix aperature)
window PC -> mp4,  mac pc -> MOV
i like CPL filter than ND filter.  CPL filter seem to make more high quality video.