I don't believe there should be vignetting with any f stop setting. Either way I tried the experiment shooting a sun lit wall in my house at f16 with the relay iris set to 4, and zebra stripes set for 85%. There is a shadow in the bottom of the picture from the window the sun was coming through though.

Here is the image www.starcentral.ca/images/mini35f16.jpg

Dennis , thanks for that .

better than I thought and better than the VF of a Nikon F3 at F16