This is a little marvel. It's just the right size for the Q, if a little heavy (heavier than the 06). Beautiful mechanics. The front rotates with aperture selection, as I think all the old Kern-Paillard lenses do, but other than that it's perfect. And it comes with a magical DOF scale too:
Nine aperture blades.
Wide open it's glowy.
But that's just wide open, stopping down half a stop would have made the lights look normal. It only has click stops at the full stops, but it's easy to set it anywhere you like.
f/2.8
f/2.0
Very pleased with that last one actually. I think I'll go post it in the photo sharing thread too.
Edit: This was shot on the original Q, but it will cover the newer sensors without trouble, because it's designed for 16mm film (the original and smallest 16mm format, but still bigger than any Q sensor).