About.com has an interview of Clive Owen by Rebecca Murray where Owen provides an actors perspective on the lengthy and difficult shots that make up so much of Children of Men.

They’re very adrenalized, those sequences, because there’s huge resets. It’s like some of those big ones are four, five-hour resets to try and go again for a take like that. So everybody is very adrenalized, gearing up to go in for one of those takes, and there’s something just a bit magical. I think that technically some of this film is pretty staggering. The operator…most of the film is hand-held and the operator did a really incredible job, I think.

The revelation that much of the film was shot on a hand-held is incredible. I’ve been on dozens of move and commercial sets and the number of times I’ve seen a hand-held pulled out I can count on one hand. If this film does not win an Academy Award for Best Cinematography it’ll be a crime, and though Owen may not say as much I’m sure he’d agree, his praise of Alfonso is lengthy.

I do genuinely think he’s a very rare and unique talent. The thing about his movies is they are whole visions. He doesn’t do that thing of pandering to what he thinks the commercial market wants. He makes his movies. He has a very singular vision and he goes out there and does that. I think he’s very special.