On my stroll in Potsdam near Berlin I ran into a fun fair(?)/kermis(?) and came to this ride: As long as I live this thing is called 'Break Dance', at least in Germany. The whole platform is spinning, with each quad of wagons spinning, not to forget, each wagon is spinning itself again. So the whole thing is just a fast spinning mess. Just for fun I tried whether I could track focus on a wagon with that lense. So with the free eye I was scanning for a wagon to aim at, aim at that with the viewfinder eye, focusing and tracking that wagon, panning until it came to the front to shoot. This all very quickly and the hardest thing was to find the wagon I wanted to shoot in all that rotating mass and then find it with the zoomed viewfinder eye. The lens was focussing fast as hell. I was really impressed. Of the shots I got, none had missed focus: After that ride I stand nearby chimping on my camera and didn't believe my eyes. Wow, that lens has fast AF! :smile::smile::smile: Btw. mounted on a D200, set to S mode 1/1000s before. I went on with a big smile in my face.