Originally posted by Sliver-Surfer Resolution means squat unless you are printing a billboard noise plays a far larger role than MP when it comes to IQ.
I set both my FF and aps-c 24mp sonys up the same (FF in aps-c mode) used the same lens and took pictures you can see the FF (last 2 photos) looks same or better in the extreme crop.
both 1/750th 100iso 50mm f5.6 (aps-c crop in FF)
Keep also in mind this is Sony's top of the line aps-c Mirrorless vs sony's base model first gen FF mirrorless.
You didn't normalize the DoF. You should have shot ƒ8 FF. That should have also normalized the noise. It's funny how all these folks who do these comparisons ignore DOF. Maybe that's the thing. People who don't value DoF, shoot FF. I you used the same lens for the same picture, then you were further away for the APS-c image, that does make a difference. Also, my image posted below was taken with a 35mm prime, but many zoom images were almost as good. I wonder if you're saying something about the quality of Sony glass. Almost all Pentax glass is clean on APS-c, even my old FA 35-80. Maybe Sony's glass isn't.
But given your gear and expertise, the FF is marginally better. Worth paying and extra $100 for, hard to say. I mean there's always going to be better... for a price. And if you pay more you expect more... so really, nothing to see here.
I wonder why my APS_c images are so much cleaner than yours... what lens did you use, I've heard weird stuff about in camera corrections to bad lenses and stuff.
https://www.pentaxforums.com/forums/10-pentax-slr-lens-discussion/302815-35mm-find-prime.html
Long story short, I have no idea what I'm looking at, or how it might be relevant to me. Even if I thought I couldn't do better for the APS_c picture (and I'm sure I could) , it still wouldn't be enough to sell me a $2000 camera over a $600 camera.