Instead of questioning District 9's unique approach, which couches conventional action-movie setpieces amid simulated news broadcasts and pseudo-surveillance footage, audiences look right past the format and focus on the story. To some degree, the blend of formats simulates channel switching or Web surfing, where a proactive viewer seeks out relevant bits of footage from different sources.

"That was (director Neill Blomkamp's) approach from the get-go," explains District 9 d.p. Trent Opaloch. "Even before there was a script, he had the aesthetic elements in place. There are two aspects to what he's doing: There's a technical aspect, where you buy the integration of CG work and live-action elements (now possible with state-of-the-art vfx tracking software). But the most important thing is that he wanted to present this fantastic situation in a way that people would receive as reality."

To accomplish this effect, District 9 alternates between an array of simulated documentary witnesses. The multisource strategy (which also uses talking-head interviews to convey key exposition) is most intense in the first act of the film, giving way to more clearly staged footage once audiences have bought into the eyewitness conceit. But it comes back whenever plausibility is most at risk (as when Blomkamp splices in a shot from a local news chopper of the shuttle taking off, subliminally cuing auds that "this really happened").

"It's a classic strategy of, 'Look ma, no artifice,'" explains film scholar David Bordwell, author of the Observations on Film Art blog and more than a dozen textbooks on film style. "From a historical perspective, this appears to be cyclical. At a certain point, a number of filmmakers decide that artful messiness is quite engaging. This is a style that gains its sense of sincerity from opposition to a clean, well-behaved movie. But if every movie starts to look like it's from YouTube, then (the strategy) loses its edge."

District 9 producer Peter Jackson was originally more comfortable with the loose ENG-style camerawork (meant to mirror raw electronic newsgathering, with its handheld energy and on-the-fly lens adjustments), while dramatic scenes were meant to have a more "pushed" (or saturated) Ridley Scott-like look -- "so you would have these two contrasting approaches," Opaloch explains. "When we started doing that, it felt really wacky and artificial, so pretty much every time we got into (the objective scenes), the cameras would come off the dollies and just go handheld."

Of course, filmmakers didn't wait until 2009 to experiment with documentary techniques. As Bordwell points out, "From World War II on, nearly every country had some sort of neorealist impulse." In America, the crime genre combined docu-style shooting with voice-of-God narration in such late-'40s/early-'50s entries as The Naked City and Panic in the Streets. Later, directors who got their start in documentary, including Stanley Kubrick and William Friedkin, incorporated verite-based techniques in such films as Paths of Glory and The French Connection. "It reaches a culmination in Medium Cool, where you have that immediacy of filming in the Chicago riots," Bordwell adds.

Nearly 40 years later, Brian De Palma advanced the hybrid form with his 2007 Iraq War thriller Redacted, weaving jihadi websites and Al Jazeera-style footage into a tapestry of "found footage" not unlike the elaborate collage of District 9. By comparison, Kathryn Bigelow's The Hurt Locker seems downright conservative, even though it marks a radical departure from the director's more classically constructed earlier work. To achieve the immersive effect she wanted, Bigelow turned to cinematographer Barry Ackroyd, whose background in documentaries had served him well with such verite-inclined directors as Ken Loach (Ladybird Ladybird) and Paul Greengrass (United 93).

"The reason she got in touch with me was because of United 93. She wanted that sense of immediacy and urgency," explains the d.p., who coached Bigelow in Greengrass' strategy of shooting long, continuous takes and letting the action move from one camera to the next. While the actors played close to the script, the camera crew was encouraged to improvise and avoid ever repeating the same take. "If in the end, the shot is out of focus, that's the equivalent of a beautifully framed shot because it betrays the emotion in it," Ackroyd says.

Some films, like Paranormal Activity or Cloverfield, take the documentary conceit literally, limiting themselves to footage captured by the characters, while others aim for realism while cheating through what Bordwell calls "camera ubiquity," where a series of invisible cameras see all (except for one another). The spontaneity comes from setting up the cameras at the right spots within an environment and then reacting to the action as it happens.

Perhaps the best evidence of how ubiquitous docu tactics have become is James Cameron's Avatar, which co-opts a docu-style vocabulary of impromptu zooms and fluid handheld lensing to "sell" the reality of its highly artificial environments. Gone is the dolly-and-crane style of Titanic, replaced by an in-the-trenches approach contemporary audiences seem to find more credible.

"The filmmaking process now is so varied and flexible that television has become more cinematic, and, almost in reaction to that, cinema has become slightly more documentary," says In the Loop director Armando Iannucci, who rejected stagey compositions to convey a fly-on-the-wall view of top-level politics. While his actors improvised from an ever-evolving 240-page script, the cameras also became part of the action.

Whether they realize it or not, reality TV-trained viewers have learned to judge not only the actors' performances, but the camera operators' as well. District 9's Opaloch has a term for it: "I think of it almost like Method operating," he says. "It's an immersive camera -- to me, that's the whole idea of filmmaking: You want to put the viewer there. I think that engages the viewer in a very visceral way."

When done right, audiences don't even see it. But study District 9 or Bruno shot-for-shot and you realize how complex -- not to mention impossible -- the realities they create really are.

[This essay originally appeared in Variety.]