..and they do pretty good AF during video. Check the first video on this French page (in comparison to canon 550D):http://www.focus-numerique.com/sony-alpha-...-news-2091.html
However, the lens is used at its maximum aperture.
Yes, and that's an issue for people who need control of exposure, although I think anyone who's serious enough would use manual focus anyways.
I don't think it's fair to compare the EOS 550D since it doesn't have full time AF in video mode and the operator did a terrible job at focus pulling. They should've tried the GH1 or something like that.
