I have an EX1 that has been back for re alignment and now has a vary evenly spread vignette at full zoom.
Here is a link for a clip on blip.tv
https://blip.tv/file/619918?filename=DasherFilms-EX1TestClip536.mov
The vignette is there at the telephoto end of the zoom. OIS makes it much more noticeable.
I have contacted my dealer and I am waiting to find out what will happen. I