I often wondered just how good the 1D's auto focus system was. You read all the stories about some bodies having a horrible time (pre-fix) holding focus and the focus suddenly shifting mid series. It had me worried, but my curiosity was still there. I've chatted with countless 1D Mark III owners online and the vast majority of them said "it's unreal, just give it a try". I tinkered with them in the store, but it's not the same as actually shooting one. Today I took my camera out to do some shooting, looking for hard to track and fast moving subjects to see how my copy performed. Granted, mine is of recent manufacture and the serial number range falls well outside of the original service notice regarding the AF problem. So it has the original fix as well as the "blue dot" fix. I started off shooting gulls on Navy Pier in Chicago. These little guys really get going, and they drop down below the top of the structures so there's plenty of background stuff for the camera to jump to if it looses focus on the subject. I was amazed at how blazingly fast and deadly accurate the AF was. I had all 45 AF points activated and shooting at f/8. The camera was in AI Servo mode. I would say a good 90% of the images were totally perfect. Here's a couple of examples: I then ventured up to the to the top deck of the Pier where the rides are. They have this carnival ride that swings the riders quickly in a circle, I mean they are REALLY moving and there's lots of chains, people and seats all in a bunch to trick the AF system. When the kids passed through the view finder, I just saw a blur and hit the shutter release. Again, practically all of the images had spot on focus like this. Color me absolutely impressed. There is nothing in this world like the AF system on the 1D MkIII. The speed at which the camera can focus coupled with the deadly accurate AF is nothing short of amazing. It makes my other bodies feel like slugs. It also takes purdy non-action pics too.