by C-M-B » Sat Feb 15, 2020 7:27 pm
I'm not sure whether this comparison qualifies but I've found that my GFX 50S (which has the same sensor as the IQ250) at ISO 100 is less noisy than the P65+ back at ISO 50 - that is with the same exact settings with regards to sharpening, noise removal etc.
But the difference is really small and would not be observable even with larger prints.
Of course the same can't be said about noise beyond ISO100-200 or during long exposures, this is where CMOS shines. But we have to keep in mind that CCD sensors can still be extremely usable at low ISOs for short exposures.
And yes, the pixel size does matter:
P65+: CCD pixel size 6 micron
IQ2 50: CMOS pixel size 5.3 micron
IQ3 100: CMOS pixel size 4.6 micron
So the IQ250 can make up the difference of 0.7 micron with its newer technology, but the IQ3 100 is another 0.7 micron smaller...and that's quite a significant difference. A lot of cameras with small micron pixels have noise issues - it's just physics.
So if you buy a high res camera, don't expect less noise.