Lighting system invented by former actor Stu Rutherford and Carlo van de Roer, used in Taika Waititi's Thor which appears to slow down time.

Time slows down to a soupy, underwater, almost strobe-lit feeling as we peer inside the mind of the Valkyrie and see her painful memories of a fruitless, horse-backed battle against Odin's warmongering daughter, Hela.

If you've seen Taika Waititi's new superhero movie Thor:Ragnarok, you should remember that shot, fleeting though it is, because it won't look like anything you've ever really seen before in cinema.

If you haven't, then that makes explaining the next bit tricky, but stay with me, because it's about how two Kiwis - one of them Waititi's old flatmate - have invented a piece of fiendishly-clever technology that big film studios should soon become very interested in.

MARVEL/SCREENGRAB A still from the sequence in Thor:Ragnarok made possible by Stu Rutherford and Carlo van de Roer.

In a warehouse in New York, two old schoolfriends from Wellington - an artist (Carlo van de Roer) and a software developer who ended up playing a version of himself in Waititi's mockumentary What we do in the Shadows (Stu Rutherford) - have been working on a giant lighting rig that can make it seem as if time has slowed down.

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Dangling a 35-foot-wide circular metal frame, bearing 200 lights, several metres in the air, then moving the light source faster than the speed of sound causes an effect that when film cameras start to roll, time almost freezes.

supplied The lighting rig on set.

"I was looking for a way to play with the way we are used to seeing time represented in photography and film-making," says Van de Roer, who began the experiment during a residency at New York's New Museum.

When Waititi visited van de Roer and Rutherford's temporary studio in Brooklyn, they began testing the idea with a quarter-size prototype model.

"Some time later, Taika and [Thor's visual FX supervisor] Jake Morrison called about an idea for the Valkyrie flashback which seemed like a cool fit," says de Roer. "We loved the idea of filming memories as moments suspended in time, yet in flux, with time and light still passing through them in a heavy, soupy way."

Rutherford and Waititi in What we do in the Shadows.

The brief, says Rutherford, was to create a "a flashback to a world where time is breaking down, so they wanted an effect where time is very much slower, and light is moving around in quite a jarring and confusing way".

When Waititi first visited, the pair say, he quickly understood how the new system changed the way a shot is staged. "He realised that as an actor you only get to make one impression, one motion for each shot, and he went away and thought about it," says Rutherford.

"There's a parallel between shooting like this and still photography," says van de Roer. "People picked up on it very quickly. Tessa Thompson [who plays the Valkyrie] was there for the longest and by the end she had become really adept at figuring it out."

supplied Kiwi firm Satellite Lab's innovative new lighting rig, as used on Thor:Ragnarok.

For example, in one shot of the sequence, which was shot on a soundstage in Brisbane, Thompson bounced on a trampoline, and the camera rolled on the third bounce, to capture a single frame of her facial expressions. In another, where Cate Blanchett's Hera throws daggers, she was given sugar packets to toss towards the cameras. The horses were shot from 18 angles running beneath the rig to ensure the right shot was achieved.

For the horses were real - even if their wings, of course, were not.

It's this reality with a tweak where Rutherford sees real opportunities for Satellite Lab, particularly when the shot involves something which is tough to recreate realistically on computer: things like faces, liquid, powder, sand. That was what appealed to Waititi and Morrison: "They wanted something based in reality, and augmented with CG, rather than just fully CG."

SUPPLIED Tessa Thompson as Valkyrie in Thor: Ragnarok.

Their other clients thus far include high-end advertising brands such as Nike and the shoemaker Christian Louboutin, althoiugh they are considering moving to the West Coast to secure more film work. Right now, says van de Roer, it's just him and Rutherford sitting in a room, but when a big project is on there's up to 20 other people involved.

Rutherford will be familiar most to Kiwis for his part in Shadows, where he ended up fifth on the credit roll as "Stu the IT guy", playing what he's described as a nuanced version of himself from some years earlier.

But acting has dropped down the agenda for Rutherford as Satellite Lab has taken off. He says he's been asked to appear in the forthcoming Shadows spin-off TV series Paranormal Unit, but only in a relatively small part and he's not sure he will be in New Zealand at the right time.

Actor turned lighting guru Stu Rutherford.

And he isn't in Thor:Ragnarok. He was in the background of one scene - which was cut from the final edit.

"When you're shooting you always assume you're not going to end up in the film, and if you do that's great," he says. "But I would much prefer that Satellite Lab's lighting stuff made the final cut, than my little bit. Anyway, Taika has told me I'm going to be on the DVD, so right now I am waiting for the DVD to come out."