The first thing I must get off my chest: if Public Enemies demonstrates anything, it's that Michael Mann's infatuation with high-definition video is becoming quite diabolical. When he used digital cameras to shoot Collateral, it made sense and it worked tremendously well; when he did the same for Miami Vice, it at the very least made sense, though it kind of failed a lot. But in his latest feature (which, incidentally, reunites him with cinematographer Dante Spinotti for the first time since their extremely wonderful work together on The Insider; I believe it's also Spinotti's first time working with digital video), I can't see the sense of it at all, except it's that Man really loves to set scenes in the dark. But you know something, people have been setting scenes in the dark for decades now, and they've all figured out how to correctly light dark scenes enough that they'll still expose film. And the trade-off is pretty steep, because if the dark scenes, save for the expected bit of video noise, tend to come out pretty well, the daylight scenes by and large look terrible - no, that's a rough word, let me back away from that. It's that there's a certain unmistakable video-ness to the lighter scenes, the way that bright points all seem a little washed-out and grimy. You didn't see any of that in Mann's last two films, but going any further down that path leads us to "and that's why Dion Beebe is a better DP than Dante Spinotti", and I am much anxious to avoid that conclusion. Anyway, my point was that quite a lot of Public Enemies looks a bit ugly, and more importantly than that, it looks cheap and chintzy, the videography combining with the frequently handheld camera to give the impression that we're watching somebody's home movies that Johnny Depp and Christian Bale happened to stumble into, in full period dress.

I'm happy to say that I don't really have any other particularly large complaints to make about the film other than that, although it doesn't need pointing out that it's a very large complaint indeed. Film is a visual medium, you know. In terms of story and character, this is quite probably Mann's best film of the 00's, in fact - and if I'd still slightly rather watch Collateral, it's mostly because I find Mann has more interesting observations to make about Los Angeles in 2004 than Chicago in 1933. L.A. is a presence in the earlier film whereas Chicago is just the setting for this film, basically.

Based upon Bryan Burrough's true-crime book about how the Federal Bureau of Investigation was birthed by J. Edgar Hoover (an unrecognisably filmy Billy Crudup) to fight the great gangster wave of the early '30s, led on the ground by the first great G-Man, Melvin Purvis (Bale). Though we very briefly see "Pretty Boy" Floyd (Channing Tatum), and we see a bit more of "Baby Face" Nelson (Stephen Graham) the public enemy of primary interest is the notorious John Dillinger (Depp). The film opens without a scrap of backstory, as Dillinger stages a jailbreak from his first incarceration following the nine-year stint from '24-'33 that set him on the road to becoming Depression-era America's most famous criminal. Hewing fairly close to historical fact without being anal about it, the movie tracks the final fourteen months of Dillinger's life, chiefly focusing not on his bank robberies, but his relationship with Chicago coat-check girl Billie Frechette (Marion Cotillard), the one humanising element in the rock-hard criminal's world.

There were two basic routes that Mann could have gone with this (ignoring the influential but very played-out Bonnie and Clyde style): film it in the manner of the 1930s gangster pictures that were informed by the public enemies and in turn influenced them; this would have been a lot of fun, but probably kind of stupid, too. The other, the one Mann took, was to make it as docudrama-like and realistic as possible, and this proves to have been a wise and pleasing choice. This might indeed be the most realistic film of his career, lacking the visual poetry of a film like Heat; though the direction is absolutely stylised, it is stylised only in small and sometimes invisible ways, largely a matter of uncommon editing patterns and Mann's oh-so-characteristic use of tighter-than-normal close-ups and medium shots. In the main, this is a rigorously natural film; I suppose it's this very motivation that led Mann and Spinotti to shoot digitally, as it permitted the use of practical lighting in places it might otherwise not have worked.

Key to this element of the film, its hyper-realism, is Depp's performance; surprisingly un-mannered for the famously inventive actor, his approach to Dillinger is remarkably stripped-down, and devoid of nearly any of the romance that most movie gangsters accrete to themselves. Other than his palpable affection for Billie, as close as a man like that can get to true love, there's nothing nice or sweet or heroic or even human about Dillinger in this film, with Depp's stern face (he smiles, I think, three times in the movie, and it's always a bit unnerving) and hard eyes - it's the eyes that really do it. You look into Depp's eyes as Dillinger, and you are not going to see a folk hero, an American Robin Hood, or any of that charming bullshit. You see a man who would kill you without flinching if you could cause any danger to his continued safety and freedom.

As Depp's opposite number, Bale gives his best performance in while, maybe as far back as Batman Begins - the sort of self-parodying tough guy thing he's been doing the last year or so isn't gone, exactly, but it works really well in the context of a '30s crime fighter. Bale has a certain authority in the role without necessarily inhabiting the depths of Purvis's mind, which is ultimately appropriate: as the plot proceeds, we learn that he is a man who bends with the wind, doing whatever is necessary to win even if that means sacrificing a certain level of basic decency. He is, in other words, nothing but a tough guy and a hard-ass, and if Bale plays him with only a trace of subtlety here or there, it is because the character does not possess any subtlety.

The film is not great, but it is very good in most respects, and a few isolated moments achieve greatness; particularly a lengthy shoot-out at Little Bohemia, the Wisconsin lodge where Dillinger and the Fed had the most violent altercation. It's an action sequence far greater than anything Mann has directed since the post-heist assault in Heat, with the camera movement, sound design and yes, the low lighting, all combining to make a confusing, hellishly violent explosion of gunfire. It's as thrilling a moment as anything so far this summer - a damn sight more thrilling than anything in Transformers 2 - and it's couched in a movie that you wouldn't dare call an action film; this is just part of the magic that is Michael Mann, that he can freely mix a study of the behavior of an essentially evil person with a documentary procedural about how the F.B.I. was formed with mesmerising, quicksilver action-movie fireworks. Once again, he's made a film that refuses to nail itself down to any one niche, and even if it's more straightforward than his recent structural and formal experiments, it's not any less ambitious or enjoyable for that.

7/10, the official review for those of us attentive to niceties of cinematography

8/10, for those who read the first paragraph with boredom and wondered when I'd get around to talking about the movie