Here's a 35/4.5 test shot from my copy, using the S1RII. The corners are pretty soft, which is what I expect for this lens, at least when wide-open. Focus is on the fence in the center of the image. Lower left and upper right corners (the shrubs) should be same DOF as the focus point, more-or-less. Of course, the S1RII is working the lens pretty hard. But still, given the parameters of the lens, you can't expect it to have sharp corners wide-open.
You should be able to click into the image to SmugMug and download the full-res 16 MB file. If not, and you want to see it, let me know.
View attachment 13956