I do not see this lens listed in the lens gallery section, so I am starting a thread for it. Here is a shot from last night at the Phoenix Zoo during a summer night opening. I use this lens sparingly, but in very low light situations it comes in handy. It was darker than even the photo makes it look and autofocus did not work, so I had a difficult time manually focusing. I use a 5D2 - maybe a 6D would have been able to autofocus in the dark?
Anyway, here is the camera JPEG with no adjustments other than downsizing. Shot at f/2, 1/8 second, iso 4000.