This is a frame from the ‘Samyang’ 14mm lens. Its slightly less than the full width/height of the a7RII because it has been straightened somewhat (1.6 degrees).
The image was processed to display tonal and textural elements and not ultimate detail but does show relative resolution across the entire frame.
Unfortunately f16 is far from optimal for this purpose but insured almost all of the frame to be in similar focus. There really isn’t much difference between the center, these edges or the far (upper) corners.

You can also see that the ACR lens profile does a decent job of controlling the infamous ‘mustache’ distortion of this lens.