I'd like to share my video:
Is an italian destroier ww2 sunk between Corsica e Sardegna in Mediterranean sea at 100m depth.
It's shot whit GH4 in 4k 25p with 7-14 pana (aperture 4-5) ISO 1250 with 2 Keldan 6000 lumen.
Edit with FCPX in 1080p.
The video is dark....for you it would have been better to increase the ISO?
I'm open to all suggestions.