I just purchased a 5D mark III and the new Canon 24-70mm f2.8L II USM zoom lens. The first time I activated Live view mode and took a picture, the camera locked up with an error 80 message and a frozen image on the LCD that wouldn't even go away when I turned the camera off. Only solution was to remove the battery but the problem kept happening every time I took a picture with Live View activated. I tried reformatting the cards and shooting only with one card, but the problem persisted, so I took the camera back to Samy's Camera, where I purchased it. The manager swapped my lens with an identical zoom lens and after a few tries was able to reproduce the error. So without hesitation he gave me a new 5D body and we tested it with my lens. The exact same problem happened when I took the first picture in Live View mode. At this point the manager brought a third 5D body and I took about 20 pictures with my lens without problems, so I've taken this new body home with me, but something tells me there's some type of communication problem between this new lens and the 5D mark III. Has anybody experienced something similar?