Cinematographer Roger Deakins had worked with world-class auteurs, innovated new techniques, and inspired countless imitators, but until 2018, still hadn’t bagged that pesky Oscar. Then, thanks to the hyper-sterile neon-hued lensing of the sleek Blade Runner 2049, he finally scored himself an elusive gold statuette. The living master found himself at a crossroads: Where does Alexander the Great go when he has no lands left to conquer?

Deakins returned to England, and to his Skyfall director Sam Mendes, for the most colossal challenge of a rich, storied career. Their new World War I drama 1917 has a structural hook: Through a herculean technical effort, Deakins and Mendes stylize the period epic to resemble a single, unbroken shot following a pair of emissaries as they carry a warning of a German ambush. In actuality, the film is composed of several long takes sutured together through slick tricks of editing. Just don’t needle Deakins for an exact number.

“No, I don’t really want to talk about that specifically,” he told Polygon in October, after a New York Comic Con panel promoting the film. “I don’t even know if I’m allowed to.”

He’s not being standoffish; this is the sensitivity of a magician asked to reveal the mechanics to his tricks, a natural defensiveness of trade secrets. When he shot the military picture Jarhead for Mendes back in 2005, Deakins tackled the trials of shooting in sequence for long days out in the desert (“running around all the time, sweating bullets,” as he remembered it), but 1917 posed entirely novel tests of his skill. He found himself newly aware of the space between his shots, and the complicated work of hiding it.

“Sam and I sat down and worked through the whole thing, gradually figuring out the action, locations, and sets,” Deakins said. “There’s a balance between wanting to keep the shot going and the possibility of it falling apart if you push it further. We had specific points where we knew we’d break, and sometimes it was because we’d finished with a location and needed to go somewhere else to continue a piece of action. Then there were also places where we knew we could put in a joint if we needed to. A bit of insurance. A couple of times, we get a great take, and the first part of one will be good and the last part of another’s good and we find a natural place to join them. But mostly, what you see is exactly how we shot it.”

The demands of Mendes’ unorthodox formal premise completely rewrote the visual language that Deakins had perfected over the years. For instance, the standard shot/reverse shot pattern that most cinematographers use to flit between two sides of a conversation automatically became impossible.

“You have to build the shot/reverse shot into the movement of the camera and the actors,” Deakins explained. “That concept has to be embodied in the one shot. It’s about choreography, between the camera and its subject. If you want a detail, it has to be fitted into the flow of the camera’s motion. We can’t be taking people out of the film for no apparent reason.”

Innovation had to be the order of the day for Deakins and his hardworking crew, packing themselves into the same cramped quarters occupied by the soldiers. “Two guys walking down a trench — you don’t want to be on their backs the whole time, now, do you?” The corridors were so narrow that Deakins’ camera operators had to walk forward while shooting behind them, leading the cinematography team to devise novel solutions. “We worked out special pieces of equipment. Our Steadicam operator Pete Cavaciuti, who I’ve worked with for a while, figured out this very lightweight system that uses a gyro-post with a Steadicam arm that all sits on a vest. There’s a stabilizer on top of it that allowed him to run forward with the camera pointing over his shoulder, while looking at the screen in front of him.”

Deakins spoke of a “great physical strain” shared by all involved, though these days, his hands-on work mostly entails framing and adjusting the lens aperture. They spent days ankle-deep in mud, the poor traction of which gave the people, jeeps, and cranes carrying the ever-mobile camera their fair share of trouble. “It was a bit of a nightmare, to be honest,” Deakins laughs.

That nightmare reminded the veteran DP that no matter his stature in the industry, new projects will always come along to expand the limits of his talents. Deakins, as unflappably affable as ever, will greet them all with the nonchalance of a man who knows that he knows exactly what he’s doing.

“I’d done long takes from time to time,” he shrugged, “when you decide a scene would be best with one evolving shot. It’s an instinctive thing. So I’d experienced this! 1917 just meant doing it on a much larger scale in a much longer time frame.” He said this like a normal person would talk about whipping up a double portion of chicken for dinner. “That was all.”