I think you are looking for a video like this:
The IBIS on the GH5 used along side the Dual-IS of the native Lumix lenses is very impressive to help smooth out shooting (especially where you are finning for example) - it was one of the main reasons for moving from the GH4 to the GH5 for me.
However.. if you can get your rig nicely balanced with floats arms and not twitchy on the pitch axis (which is the main movement visible) and neutral underwater (let it go and it just floats in front of you) then you are not fighting to keep it steady, and so you will be able to use the water to dampen any micro judders and have nice steady shots with the cameras even without stabilisation - like the GH5s. (Having a top mounted monitor and big dome a prime example of how to make a rig twitchy
Other things would be filming in 60p and playing back in 30p (this removes the visibility of bumps in the footage and gives you super nice slowmo) - what I've been doing recently is filming at 30p and playing back at 24p - this gives you a 20% slowdown, so helps with any judder yet isn't slow enough to notice you've slowed it down.
Having both the GH5 and GH5s - its a hard choice, but the lure of DCI4K and the much better ISO performance makes me choose the GH5s.
- Interceptor121 likes this