I'm confused… but that's not necessarily a bad thing here :-)
I always thought an increase in ISO results in the same noise level as an underexposed capture pushed by the respective value.
So ISO50 underexposed by one stop and pushed in post by 1 EV is literally the same as shooting at ISO100.
Back in the days I did that test with my P45 and the results were as they were supposed to be.
Yesterday I did that test again. And as I was so perplexed about the results I did it again today under different conditions.
The underexposed shots at base ISO but pushed in Capture One by the respective values look much better than shooting at higher ISO.
The only explanation I can think of is shadow recovery and noise handling in Capture One has very much improved (my former test was done in C1 3.7 something).
Or has anyone a better idea about that? Has anyone discovered the same?
Here are the comparisons (same settings for all captures, no sharpening, noise reduction for luminance and color as written on the crops).
The difference at ISO50+1/ISO100 is not so obvious (in some areas of the capture it is) but at ISO200 it's a big difference.
Not only noise - all tonal transitions in the pushed base ISO shot look much better.
I ran that test with my P21+ as well - with the same results (at ISO100+1*/ISO200 even more obvious as with the P45).
*ISO100 is base ISO on the P21+