Super helpful information. Looking forward to trying HR mode in ISO 100 during the day and ISO 1000 at night. Thank you!!!I have now different E-M1II as I've returned the first one because it was in combo with bad 12-40 f/2.8 (new one is good). That allowed me to do basic measurements for the second copy.
I found that differences are minimal. Differences are at max 0.05 EV in DR and 0.2 dB in SNR.
But I did now measurements for the high resolution mode (HR mode).
Here is table which shows results for read noise, gain and full well capacity for the second E-M1II (I didn't measured ISO500, 640, 1000 and 1250 for normal mode) and comparison with high res mode.
High res mode works here as "synthetic sensor" with given parameters.
View attachment 862710
Next is the graph for dynamic range (DR). It's the graph from the first post but with added results for HR mode.
View attachment 862711
The last graph is for signal-to-noise ratio (SNR) and again it's the graph from the first post but with added HR mode.
View attachment 862712
Measurements for the HR mode show modest improvement (~0.7EV) of DR where best results are now at ISO100 and ISO320 (~13EV) and not ISO250 as for the normal shots.
More interesting is almost 5 dB improvement of SNR. That's really significant improvement and it means that daylight images should be at least comparable to those from Sony A7III or Canon 1DXIII.
Another interesting finding (for RAW shooters) is that optimal ISO for night hi-res photography is ISO1000 as it combines lower read noise with better highlight protection than maximum ISO1600.