From Searching for Sonny — First Feature Shot on DSLR | Gadget Lab from Wired.com:
The team used a Canon 5D MkII for the shoot, although oddly paired with Nikon lenses — the director of photography Jeffrey Waldron has a collection of old manual glass and it was cheaper to just grab a converter than load up with new Canon optics. It also meant that the apertures could be controlled. Apparently, when the 5DMkII is is shooting video in Live View mode, the aperture goes auto, meaning no control of depth of field.