Understading Photons to Photos graph for my X-S10 (or any other camera)

Tom45 wrote:

So recently I've noticed that casual snap and camera's EV being on 0 just doesn't cut it for some scenes that have a lot of dynamic range, and I'm reading around about it, trying to learn more how to protect the highlights and use the histo.

But also it seems that ISO plays a role and I found the Photons to Photos website and two graphs with X-S10 data plotted.

One is Photographic Dynamic Range vs Iso, another is Photographc Dynamic Range Shadow improvement vs Iso.

I went thru few videos that comment on these graphs for astrophotography but I got lost in the jargon...so to put it simply, what would be the main takeaway for my camera regarding these two graphs?

PDR graph: You lose the ability to record dynamic range as you raise the ISO. A scene with very high DR can exceed your camera's max capacity of 10.4 stops at ISO 160. Raise ISO and that gap gets bigger.

PDR (Shadow Improvement) graph: Your camera graphs flat which means it's effectively ISO invariant. There's something else for you to research. It's pretty esoteric and I wouldn't waste too much time.

On the PDR vs ISO graph, there's a slight bump from 400 to 500 ISO, 500 having slightly higher PDR number than 400...what would that signify in real life scenario and use case, should I avoid ISO 400 or something else?

On the other graph, PDRSI vs ISO, ISO 400 has 0.07EV value, ISO 500 has 0.49...again I'm trying to understand what does that imply.

Fuji buys their sensors from Sony. Sony bought a patent from Aptina (now ON Semiconductor) for what is called a dual gain or dual impedance sensor and that's the type of sensor in your camera.

It's almost like your camera has two sensors. It has two read channels with different impedance levels and reading the sensor can be switched between the channels. The bump you see in those graphs is the switch between channels. The first channel is optimized for more exposure (low ISO values) and the second channel is optimized for less exposure (higher ISO values). Fuji throws the switch in your camera for ISO values above 400.

It's a real difference but not a big difference. I wouldn't modify my behavior for it.

If someone can simplify this to me, would be grateful thanks