Get Sony FE 28mm f/2 at B&H Photo.
This study is definitive and confirmed by other (not published) series at similar distances.
For anyone contemplating the Sony 28mm f/2, this is a MUST READ / MUST SEE.
Includes entire-frame images up to 24 megapixels as well as large crops from f/2 through f/13.
I recommend that wide angle shooters stick to the Zeiss Batis 25mm f/2 Distagon, which is in another league above the Sony 28mm f/2.
An order was put in for lighting as sunlight together with the deep cloud shadows and a full rainbow, but it was not honored, and so we have flat even lighting, not so pretty but very good for evaluating sharpness across the frame.