I have just finished decomposing the various codecs used by the camera to record on the memory card and I have to say I am disappointed.
I had previously looked at endless comparisons between the various codecs to conclude there is not much difference in it but now that I have looked myself I am even more frustrated. I had hoped that the 150 Mbps 422 10 bit color codec was going to be enough for HDR but frankly this is really poor beyond my expectations obviously the camera internal processing is not strong enough to compress this signal real time and make it usable.
If anybody fancies looking into super technical stuff the findings are here http://interceptor121.com/2018/08/13/panasonic-gh5-demystifying-movie-recording-settings/
I am now wondering if I should fork some serious cost and invest into V90 memory cards to use all-intra or should I just not bother entirely and use the 100 Mbps codec I am curious to see if anyone has experience with all intra at UHD resolution? I already know myself this has not enough headroom to compare with external recorder but just wanting to check it out