Filming Real Fire: ‘The Lost Bus’ and the Art of Authentic Chaos

RedShark News
Inside the making of The Lost Bus, where the team ditched virtual sets to shoot real flames, dusk light, and dynamic camerawork for a visceral survival thriller.

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At one point in The Lost Bus the heat from the fire surrounding the titular vehicle is so intense that the imagery turns abstract with just flickering black silhouettes against dark orange.
“Paul wanted it to be like the children’s game of peek-a-boo – when you have to close your eyes so you only see fractions of movement,” says cinematographer Pål Ulvik Rokseth of director Paul Greengrass’ motivation. “It's just a wall of smoke and amber like a horror film or a sinister kind of science fiction. It’s a nightmare experience.”
Given that this based on fact account of a bus load of primary school children stranded in the middle of a raging inferno features actual kids the only way to tell it safety first was virtually. At least, so they thought.
ILM worked up pre-visualization for the journey the bus would take on a Volume stage in which the set would be surrounded 360-degrees by LED panels.
“The plan was to light with the LED wall and also for the actors to see and react to the environment,” Rokseth explains.
They were pretty advanced down the virtual road before Greengrass got cold feet. “I just felt it wasn't who I am as a filmmaker,” he said in a QA following the film’s screening. “It didn't feel ultimately real enough for me.”
It appears that the stop-start calibration of camera tracking with digital backgrounds was anathema to Greengrass’ signature fluid docu-style.
“It was just so much more inspiring for the actors and for the camera team if we were on a moving bus reacting to actual fire and smoke,” says the DoP who previously shot Greengrass’ docu-drama July 22. “We found that we could tell the story with more realism and more dynamism if we shot it practically.”
They located production to an abandoned campus in Sante Fe, New Mexico with enough space for roads and to create traffic and laid gas lines to burn controllable jets of fire.
This gave Rokseth the challenge of recreating lighting conditions realistic to those of huge wildfires which effectively block out most of daylight.
“Real wildfires produce this strange, occluded light — like a prolonged eclipse but there was no way we could recreate that over such a large surface area so we shot almost the entire film at dusk. Hopefully, it doesn’t feel like fantasy fire; it feels lived. That authenticity was always the goal.”
When filmmakers shoot at magic hour they are normally seeking that romantic sunset glow which looks so good on skin tones. Not here. With burnt faces caked in soot the aim was to throw the characters into an apocalypse.
“Pål has this wonderfully unvarnished aesthetic that I share,” Greengrass explains. “I told him I didn’t want to ‘light’ this film in the conventional sense. I wanted the fire to light it as much as possible.”
They rehearsed sequences during the day then shot just a handful of passes in the 90 minutes preceding, during and just after dusk. Much of the daytime was given to practicing safety procedures and timings for the gas burner FX.
Rokseth says, “When you shoot with Paul you never set up a shot. You shoot the whole scene in one, so you have to light 360. It's more like observing and documenting the story within the parameters that he sets.”
In this sense, he says filming The Lost Bus was like capturing a concert performance. “You can prep and prep and do whatever you can to make everything work but when you go on stage you have to deliver. Paul’s approach to this story was for us to go in and document what was happening in front of us as if we were seeing it for the first time.”
Since gas burners output a yellowish light rather than the variety of warmth familiar from burning carbon, Rokseth had to augment fire elements with tungsten lights, backlighting through heavy smoke FX.
He populated the set with cherry pickers and condors “like football stadium gantry lightning” as well as LED Tungsten SkyPanels. “By dimming those down and making the tungsten bulb glow is where I started to find the right characteristics of fire mixed with the power of the actual flames.”
The bus interior was lit with small LEDs and tubes to fill in the shadow and the DP relied on the ARRI Alexa 35 to do the rest.
“The Alexa 35 has an enormous amount of dynamic range, especially for fire. The colour reproduction is one of the best I've seen, the reds become even more vibrant plus you can see all the way into the fire so we can pull it back in post.”
Scenes were principally shot two camera with coverage fleshed out with pocket DJI Osmos, Red Komodos hard mounted on vehicles and DJI Inspire 3 drones.
Rokseth himself operated A-cam while James Goldman commanded B-cam. Their choreography was a key part of prep.
“The vibe of the whole film is to tell the world from the point of view of the characters. We prepped moves with the actors during the day but in a sense that goes out of the window when you film when you are in the heat of the moment guided by instinct. You cannot anticipate. It is not a knowing camera. It is basically observing from the character’s perspective at the same time we have to give the editor latitude to play with so we can’t leave a shot too early.”
Naturally, this piles a lot of responsibility on the camera operators which is why Rokseth likes to take the lead.
“You can always have another camera pick up the shots that you don't get but to tell this story it's difficult to send in somebody else. It’s better for me to do it  myself because then it's my decisions and because it's in the heat at the moment I can do this instantly. I couldn’t do that remotely by relaying instructions to another operator.”
While Rokseth would follow one character – Matthew McConaughey’s hero bus driver for example, the B-cam would go in another direction. The trick was not to capture each other in frame or get in each other’s way.
“Not only do we have stay out of the other shot but also have to know what you did in the first take so on the second take you can do the opposite,” he says.
There was no time to review on monitors so Greengrass would give immediate feedback after each take. “Paul was our eye. He tells us what worked, what we missed and what he needed more of.”
Their choice of zoom reflected Greengrass’ reportage roots. “A zoom has long been the documentary maker’s choice and with a Super 16 format you have a tool that is light, nimble and able to tell multiple shots in one take,” Rokseth says. “We wanted the package to be the digital equivalent of Super 16.”
This turned out to be the Canon 8-64mm T2.4, which enabled the operators to carry handheld or shoulder mounted and frame for wide or tight shots. It also meant cropping into the S35 format and halving the 4.5K resolution but by shooting open gate ArriRaw the picture could be blown back up to full frame in post and the output returned to 4K.
With Stephen Nakamura of Company 3, Rokseth built a LUT which was a mix between a print emulation and film stock emulation. “If you shoot everything on one film stock it's more practical because you don't have to divide everything up into interiors, exteriors etc and since LUTs are essentially film stock, I usually just tend to use one for the whole project.”
He describes the colour scheme as “red fire, black night and weird amber universe” which contrasts with scenes set in normal daylight.

Scenes of the fire get more abstract and almost expressionistic the deeper the bus travels into the conflagration. This is most apparent in a scene in which school teacher Mary (America Ferrara) gets out to look for water at a trailer park. The action here, which includes exploding gas tanks, is shown with flickering almost strobe-like effects in black silhouettes against dark orange.

“We had a massive amount of smoke effects and it's disorientating. When you see real wild fire references and when you talk to the firefighters who were there at the real event in 2018 you realise how much of a horror scene it was.”