From Keighley’s point of view, The Dark Knight is a long-time dream come true. “We’ve tried to get a filmmaker to shoot a film in IMAX for 40 years,” says Keighley, who ticks off Coppola’s Apocalypse Now as one project he pushed for. “But everyone said, the cameras are too big, too heavy and too noisy.”

With The Dark Knight, all the action sequences were shot in IMAX, and later intercut with 35mm film. This film also marks cinematographer Pfister’s sixth collaboration with director Chris Nolan, which began with the indie hit Memento and was seen most recently in The Prestige.

As a team, Nolan and Pfister are notable for their efforts to adhere to an “in-camera” ethos. Pfister famously avoids the digital intermediate process that has become commonplace among Hollywood filmmakers for the ability to tweak nearly everything about the image. “If it ain’t broke, don’t fix it,” Pfister comments. Though “The Dark Knight” does include digital visual effects, many of the effects are captured in-camera. In one notable sequence an exploding four-storey building was destroyed for the filmmakers, who shot it in Chicago. In other words: What you see in this film may actually have been there on the set.

That makes it all the more impressive that the very intense action sequences, which include the six-minute opening shot of a bank heist, were shot in IMAX. Pfister revealed that he and Nolan have long been fans of the IMAX format. “There’s no better image quality,” says Pfister. “And Chris wanted to enhance the film-going experience.”

In fact, Nolan had an earlier experience using the IMAX format. The 2005 Batman Begins, Nolan and Pfister’s first Batman picture, utilized IMAX’s DMR (Digital Remastering) process, in which film shot in 35mm is transferred to IMAX’s 15/70 format, for sections of the film. “That’s what gave Chris the idea of originating in native IMAX,” says Pfister. [As an aside, Keighley reported that 22 films have used the DMR process to release IMAX versions.]

But Nolan and Pfister didn’t plunge headlong into IMAX production. “We shot lots of tests in Chris’ garage,” says Pfister. “Very guerilla-style, we drove down Hollywood Blvd. without a permit, shooting. We needed to get an idea what we were getting ourselves into.”

Next, Nolan began to pick scenes he wanted to do in IMAX. “He had to sell the studio,” says Pfister, who admits he was excited to shoot in IMAX, whose image is 9.5 times bigger than anamorphic 35mm. “He needed to answer in his own mind if he could finish the film within the post schedule.”

He decided he could, and, ultimately, 28 minutes of the film were shot in full IMAX. “It was very detailed and very complicated, but we wanted people to see it on the IMAX screen,” says Pfister. Keighley noted that Nolan also likes the sound mix best in IMAX. The IMAX theatre is a digital surround sound system that delivers multi-channel, uncompressed, full fidelity sound. IMAX’s amplifiers generate up to 14,000 watts of power. That opening bank heist sequence, says Pfister, is notable for the IMAX sound because where the gunshots are both very loud and seem very close.

But an IMAX camera also weighs in at 100 pounds, compared to the Panaflex’s 32 pounds. Because Nolan favors a hand-held look, the first test of shooting in IMAX was Gorelick’s ability to operate the 100-pound Steadicam rig. That test came immediately, with the shoot’s first filmed sequence: the movie’s demanding opening sequence. The bank heist was located in an old post office, with very hard, very slick marble floors. “Bob had to do a running shot with the Steadicam and the arm broke off,” remembers Pfister. “My back was stressing,” admits Gorelick.

“At the beginning, Chris [Nolan] asked if we could do anything with this camera,” Pfister adds. “At the end, he’d ask, is that as fast as you can run? It became second nature after awhile.”

Framing for IMAX is quite different than for a 35mm image, said Gorelick. “You leave much more headroom,” he said. “The cross-hair is just under the eyeline. The practical reason for that so that audiences don’t have to crane their heads back to see. For a production like this, they extract whatever part of the negative they want, and it was usually the center.”

Geryak reports that lighting wasn’t that different than a typical 35mm shoot. “The biggest problem was hiding the lights,” he says. “In the post office where the opening scene takes place, there were 12 big windows. We put up one Xenon light per window. With the IMAX camera, you get a lot of clarity; you can see all the details.”

Shooting in IMAX also had a nuanced impact on the editing, by Lee Smith, said Pfister. “Christopher was very conscious of the IMAX format,” he said. “In the opening, six-minute bank heist, which was cut during principle photography, they let scenes linger on the screen a little bit more [than usual].”

Pfister added that director Nolan didn’t want to treat The Dark Knight any differently from an ordinary 35mm film. “We did all the conventional things we’ve done with 35mm for years.” Pfister also credited “two great key grips, [gaffer] Perry Evans in London, fabulous focus pullers, and IMAX consultant Wayne Baker.” Depth of field is very difficult in IMAX, he says. “The fastest lenses are 2.8; one gets down to a 1.4, losing flexibility which made it more challenging for Cory and his boys,” adds Pfister, who said he used “mostly Hasselblad lenses.” “The team did a great job in figuring it out.” But he couldn’t get the flares he wanted in one end scene. “I always imagined it with flares, but I couldn’t quite get them,” he said. “There’s a much shallower depth of field and the image is very wide.”

During production, recounted Pfister, Nolan remarked that, “in a weird way, shooting IMAX is like shooting Super 8mm.” “There’s only one lab that develops it, it comes in 3-minute loads,” says Pfister, half-joking. “And you send it away and get it back in a week, so you have weeklies, not dailies.”

The IMAX sequences were scanned at 8K resolution and turned into an anamorphic negative. These sequences that originated in IMAX “probably do look a bit sharper than those shot in 35mm,” concludes Pfister. “You can notice a difference,” he says. “Even in the material that’s gone to DVD, the IMAX material is sharper. “It’s called over-sampling,” notes Keighley. “It always looks better when you start with a larger format, and it’s harder to mess it up.”

Shooting in IMAX posed numerous challenges. With only 3 minutes per load, the production used three IMAX cameras. Then there’s the weight of the IMAX camera. “I was 6’4″ when I started,” jokes operator Gorelick. “And now I’m 5’10”.”

With the 360-degree sweep of the Steadicam rig, Geryak also found it difficult at times to find places to hide lights. “When we had to light for large action sequences, such as the bank heist, the lights had to be moved further back,” says Geryak. “It was trickier.”

Finally, and significantly, the cost of shooting in IMAX is four times that of shooting in 35mm, reveals Pfister, who notes that, without a very large camera blimp, productions have to loop sound. “That’s why it’s too difficult to shoot an entire movie in IMAX,” he concludes. “The problems are still a roadblock.”

But the IMAX shoot went smoothly, and Pfister raves about the result, after having just seen a screening of an IMAX print. His advice to movie-goers? “You must see this film in IMAX,” he says. “It looks beautiful.”