The opening shots and some of the other night shots (e.g. in the bus) are shot on the Sony HDCAM. Thats why they have the huge amount of video noise. The posterization could be on purpose, but is more likely due to high gain boost.
Being a photography nut and a sucker for cinematography, i think the use of the Sony HDW-F900 (HDCAM 1080p24) in this movies shows excatly why HD is NOT ready yet to replace film.
The HD sequences in Ali look terrible IMO. They have this typical HUGE depth of field effect that is unavoidable with HD cameras because of the small size of the sensors. Proper subject isolation through shallow DOF is not possible with HD yet which makes every HD scene in a movie look like nothing more than a highres home-made video.
I didn't like the cinematography of 'Session 9' (also shot on HD) for the same reasons. Yuck.
In ALI its especially sad, because the difference between the absolutely stunning film based cinematography and the poor HD shots is so dramatic. They used a huge range of lenses in the film based scenes, with some breathtaking shots, including many with a great use of shallow DOF.
This makes me really worried about Episode2, which is shot with the same Sony HDW F900, i think. We'll see if they somehow get the 'video' look away in that.