In this post, I’ll present pairs of images made with the a7RII on both sides of the conversion gain transition, corrected in post as explained here. The base ISO is 12800.
The difference in noise level is apparent.
Sony a7RII conversion gain visual changes — base ISO 12800
Well done! Oh, I am little disappointed about till ISO640 would be isoless! Hm, for AUTO-ISO setting 64 to 640 and then push with EV till +4 or 5?
Hm, it seems that a7rII is much noiser then a7II.
Actually, it’s the other way around, if you correct for the resolution differences.
There’s no reason to ever use an ISO setting below 100. I’d leave AutoISO out of the mix, too. Here’s the plan: ISO 100 until you can switch to ISO 640 without blowing highlights.
Jim