Not so much a stability test, more on focus-handling so its recorded in slow motion to study how smooth the focus goes. As you can see, sometimes its a bit stuttery.. Probably because of the short distance one has to move the handle for it to change focus spot from one to another. If we could do the focusing distance a bit longer with the handle, it could minimize ugly stutter.
Please watch it in HD if possible. (aliasing is wonderful isn't it?;)