Opticallimits

The Sony A7R V manipulates RAW files.

The vignetting figures of the 20-70mm f/4 G are unreal.

I've tried 3 different RAW converters, and none shows any relevant vignetting at 28mm f/4 and just a bit at 20mm f/4.

Should I say I'm surprised? :-)

Put it on a Nikon Z camera with adapter; guess that ought to do the trick. :-)

Out of curiosity, Klaus: did you run a quick and dirty test with an older Sony camera? I'd be curious about when Sony baked the manipulation into the camera firmware.