Canon USA published the recently announced firmware update for its EOS 5D Mark II digital SLR which enables manual exposure during video capture.
As well as the manual exposure video functionality, EOS 5D Mk II firmware v1.1.0 includes fixes to the lens peripheral illumination correction, auto lighting optimizer, battery information display, and depth-of-field preview button functionality, as well as correcting menu errors in certain languages.
You can download it from here