Some have hailed it as a masterpiece, others have complained it left them cold. Personally, seeing it on 70mm, I found Dunkirk a highly immersive and visceral film, cinematic in the truest sense of the word. The huge, sharp images free from any (apparent) CGI tampering, combined with the nerve-jangling gunshots and rumbling engines of the superlative soundtrack, gave me an experience unlike any other I can recall in recent movie-going history. I can imagine that it was less effective projected from a DCP onto a smaller screen, which may account for the underwhelmed reactions of some.

But however you feel about Dunkirk as a film, it’s hard not to admire its technical accomplishments. Here are five unique aspects of its cinematography.

 

1. It was shot on two huge formats.

Director Christopher Nolan has long been a champion of large-format celluloid capture, eschewing the digital imaging which has become the dominant medium in recent years. “I think IMAX is the best film format that was ever invented,” says Nolan in a DGA interview. “It’s the gold standard and what any other technology has to match up to, but none have, in my opinion.”

Imax is a process which uses 65mm film (printed on 70mm for exhibition, with the extra space used for the soundtrack) running horizontally through the gate, yielding an image over eight times larger than Academy 35mm. Following some test shots in The Prestige, Nolan captured whole sequences from The Dark Knight, The Dark Knight Rises and Interstellar in Imax.

For Dunkirk, Nolan and cinematographer Hoyte van Hoytema, ASC, FSF, NSC were determined to eliminate 35mm altogether, to maintain the highest possible resolution throughout the movie. Imax cameras are noisy, so they shot dialogue scenes on standard 65mm – running vertically through the gate – but Imax footage makes up over 70% of the finished film.

 

2. The movie was framed with three different aspect ratios in mind.

Those who watched Dunkirk in an Imax cinema got to see the native aspect ratio each sequence was captured in, i.e. 2:20:1 for the standard 65mm dialogue scenes but the much taller 1.43:1 for the Imax material, the bulk of the film. Those, like me, who attended a standard 70mm screening, saw it in 2:20:1 throughout. And those hapless individuals who watched it digitally apparently saw the standard Scope ratio of 2.39:1, at least in some cases.

This means that, when composing his shots, van Hoytema had to have two ratios in mind for the dialogue scenes and three for everything else. “Framing was primarily for the 2.40 [a.k.a. 2:39:1], then protecting what was outside of it,” 1st AC Bob Hall explains. This left close-ups, for example, with a large amount of headroom in 1.43:1, but the huge size of Imax screens made such framing desirable anyway.  “Imax is such an immersive experience that it’s not so much the composition that the cinematographer’s done as where your eyes are going on the screen that creates the composition.”

 

3. Parts of the camera rig were worn as a backpack.

Breaking with the accepted norms of large format cinematography, van Hoytema captured a significant proportion of the movie handheld. The 65mm camera package weighed over 40kg – about three times the weight of a typical Alexa rig – with the Imax camera only a little lighter. To avoid adding the weight of the batteries, video transmitter, Cinetape display and Preston (wireless follow focus) brain, these were placed in a special tethered backpack which was either worn by key grip Ryan Monro or, for water tank work, floated on a small raft.

Unfortunately, Hall quickly found that electromagnetic interference from the Imax camera rendered the Cinetape inoperable, so he ended up relying on his extensive experience to keep the images sharp. “I had to go back to the technology of the 1980s, where I basically guess how far famous people are from me,” he remarks drily in this enlightening podcast from Studio Daily.

 

4. A periscope lens was used to shoot spitfire cockpit interiors.

“I wanted to tell an intensively subjective version of this story,” says Nolan. To that end he requested over-the-shoulder views out of the windscreens of Spitfires in flight. Furthermore, he wanted to be able to pan and tilt to follow other aircraft passing by. Given the huge size of the Imax camera, there was no room to rotate it within the cockpit. Instead, custom periscope lenses were built which could snake over the pilot’s shoulder, and pan and tilt independently of the camera body, using prisms to maintain the correct image orientation to the film plane.

Other glass used on Dunkirk included an 80mm Imax lens belonging to Nolan himself, and converted stills lenses.

 

5. At one point the camera sunk to the bottom of the sea for an hour and a half.

A specific Spitfire POV required was from a damaged plane diving towards the sea and hitting the water. The practical effects department devised a catapult to launch an unmanned mock-up from a ship, the grips built a crash housing for the Imax camera which would be inside, and a plan was devised to recover it before the mock-up sank. But they weren’t quick enough, and the crew watched the plane and the camera disappear beneath the waves and plunge to the bottom of the English Channel, where it sat for 90 minutes until divers retrieved it. Incredibly, once dried out and developed, the film footage was found to be completely undamaged. “The shot was all there, in full colour and clarity,” says van Hoytema in the American Cinematographer article. “This material would have been lost if shot digitally.”