2FreshMedia has posted three side-by-side comparison videos comparing video capture by Lumia 925 camera to those by competitor flagships. These are just not an OIS tests per se, but rather they have compared video capture quality of the smartphone cams.
Lumia 925′s camera captures most details and impresses with clear and smooth video capture. It betters all three competitors in providing highest quality video. Even the purple flare looks less on Lumia 925 in comparison against Xperia Z.