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Danny Boyle shot almost the entirety of zombie horror sequel 28 Years Later on a iPhone 15 which succeeded in immersing the viewer in the heart of the gory, disorientating action at the same time as it presented technical challenges for the VFX team.
This was especially the case in sequences shot handheld with either a 20-camera or a 10-camera lightweight 3D printed rig arrayed in 2.76:1 widescreen aspect ratio.
“Danny is driven by a kind of in-camera realism but when you're doing something as complex and ambitious as this with iPhones there's a lot of limitations we were perhaps the first filmmakers to encounter,” says Union VFX’ Dillan Nicholls who was DFX Sup on 28 Years Later working with overall VFX Supervisor Adam Gascoyne.
Union VFX have worked on previous Boyle projects including Pistol and T2 Trainspotting and because of that relationship knew the facility could handle what was thrown at them.
Boyle and cinematographer Anthony Dod Mantle not only wanted the mobility of the phone camera but leant into the aesthetic generated from the device’s limitations.
“It's not the most VFX friendly source media but that's not the look they wanted. They don't want that clean Marvel superhero look. That's exactly what they were trying to get away from.”
For example, many of the scenes of arrow hits were captured using the rigs. Union were tasked with rebuilding a scene from up to 20 cameras in post, match-moving each one of the cameras to get them aligned and synced correctly to match the edit before they applied VFX.
“If we're creating a CG arrow it was like having 20 shots in one and they needed to exactly line up. Any prep or compositing work that you're doing on one angle of those 20 has to ensure looks the same. It's like doing stereo 3D work where, you've got the two eyes. It needs to look the same from each of those 20 different eyes that you're going to see in quick succession, otherwise, it's kind of going to kind of bump.
“It's a bit of an unusual thing to do and our pipelines are not exactly set up to do 20 very fast cuts and make that into effectively one shot that works from multiple angles. Certainly doable but slightly odd and achieved through meticulous planning.”
“It's a bit of an unusual thing to do and our pipelines are not exactly set up to do 20 very fast cuts and make that into effectively one shot that works from multiple angles. Certainly doable but slightly odd and achieved through meticulous planning.”
The ProRes files meant that the team were dealing with chroma subsampling of 422, less information than is normally required for keying.
“It's very difficult to work with because there's less information in the colour channels. You’re better off with a green screen than a blue screen but still not very effective. So for the Causeway Chase, which could have been a big blue screen or green screen shoot, we used gray screens and roto. There's other advantages to not using blue or green screens which also played into the decision but one of the reasons was we knew the cameras wouldn't cope very well with keying.”
Nicholls continues, “The sensors also offer quite a limited dynamic range. With the fire shots, it clips at a certain level and you can see that in the cinema. You can see that you're not seeing detail in the whites of the fire in the way that you would if it was shot on Alexa or on film. Our task was just to ensure that when we're adding our fire simulations we ensure that they're clipping and that they match the same quality that you get from the iPhone.
“It has a particular kind of noise and artefacts that another director or cinematographer would have asked us to remove but this was actually the aesthetic they wanted. So all the VFX we put in can't look too clean. We needed to kind of break it. We needed to make sure it has the same limitations as the iPhone.
They found other challenges with using the iPhone. The metadata from the pinch Zoom didn’t feed through correctly into post. There was a difficulty too in matching the video’s motion blur which Union haven't fully understood yet.
They found other challenges with using the iPhone. The metadata from the pinch Zoom didn’t feed through correctly into post. There was a difficulty too in matching the video’s motion blur which Union haven't fully understood yet.
“There were certainly challenges where we were mixing a lot of CG with live action where it would take quite bespoke work to get the correct matchup. The iPhone seems to constantly adjust some of these things internally.”
Dod Mantle wanted to use the iPhone auto-stabilisation feature. “It’s great for amateurs like you or I but it breaks the math of how you track cameras,” says Nicholls.
“We knew this beforehand and were able to advise Anthony that if he used auto-stablise there would be some limitations on what we can do. Basically, it breaks the image so that parts of the image slide around. Match move is a very much a mathematical process based on parallax. It's not like compositing where you can eyeball in. With match move it either works or it doesn't and if you start automatically moving pixels around without having a way to undo that then it gets difficult. We had to be very flexible and did find ways of working with it using multiple camera tracks at different layers and depths.”
Since then, Union VFX have been talking to Apple about whether they can provide that data. “We were honest about the areas that we struggled with if they wanted it to be used more frequently for visual effects.”
It’s possible that Apple might let users invert the stabilisation data so that a director and cinematographer can use the tool as they wish on set but it would be possible to then invert it, for VFX, then reapply back.
Union worked on around 930 shots but the total count is much higher. “Danny likes to keep everything going in the edit right up until the end. We certainly worked on more shots than are in the final edit.”
Holy Island (aka Lindisfarne) in Northumberland was the real life location for the survivors community in 28 Years Later. It even has a causeway, but it winds and curves, while used as the basis for photography the linear causeway in the film was a CG construction from photography at Bovingdon.
The casting of child actors, notably 13-year-old Alfie Williams playing Spike, limited film time – especially tight at night. It’s one reason why the nighttime Causeway Chase was staged in the studio. The set contained a 100-metre ankle deep water tank and the sequence contained around 130 shots
“We would get a lot of the water splash interactions as they're running through the water in-camera, but everything else was full CG water extensions.”
A lot of work into the night sky of this sequence too. Boyle’s idea being, what would the UK be like if there was no electricity and no pollution for 28 years?
“He was really excited that we create something with amazing kind of nebular skies. Our base reference were photographs taken at the Kielder Forest Observatory in Northumberland and added some reference images from the Hubble telescope of the Carina star birth nebula, so it feels hyper real and magical.”
Arrows were safety arrows drawn in the bow on set and then dropped rather than fired. CG took over the arrows in flight. Actors wore blood squibs to achieve a blood explosion on camera augmented by VFX.
They added flies to the deer heads and made them more gory and created the umbilical cord in the baby birth scene “but even here they most of that achieved on set.”
For a scene in a Happy Eater fast food restaurant they added layers of smoke. “You can generate some smoke on set to get feel for how it would look, but essentially we needed layers of benzene across the interior of that building and it’s not something that you're ever going to achieve practically doing multiple takes.
When the gas ignites in the Happy Eater, VFX augmented the stunt performers wearing protective suits, to look as if set on fire, or replaced them with digi-doubles.
A fox running out a cottage was shot in camera but two sequences of herds of deer and a murmuration of birds, were largely Union’s work.
“We wanted a Jurassic Park moment, giving that sense of nature having taken over the landscapes. It was a case of taking what was there in the photography, the shapes of the fields, and thinking what would that look like if the farmer had suddenly abandoned it.”
A fox running out a cottage was shot in camera but two sequences of herds of deer and a murmuration of birds, were largely Union’s work.
“We wanted a Jurassic Park moment, giving that sense of nature having taken over the landscapes. It was a case of taking what was there in the photography, the shapes of the fields, and thinking what would that look like if the farmer had suddenly abandoned it.”
The actors and extras playing the infected wore prosthetics of body parts on top of shorts requiring significant cleanup of. “They're wearing shoes running around in the field so those needed removing or replacing. In sequences where they're wearing harnesses the infected needed a complete body rebuilds.
“These are maybe trivial or straightforward things but when you're talking about hundreds of shots and needing to paint out these costumes on several hundred extras that is a serious amount of work. It requires a lot of planning.
The island was a DMP (digital matte painting) environment. It’s a crucial story point, and the filmmakers were very conscious to establish its location in in relation to the mainland. “This explains why it's safe and why they’ve made a home there. This mean that the DMP asset couldn’t be just a one-off that you see from one angle where you can sort of fudge it. It's supposedly a 1.5 mile long Causeway so everything had to be mathematically correct in our asset build to enables you to then film it from whatever angle is needed to tell the story.
“Some of those angles are quite wide therefore, there's less emphasis on the detail, but then they would ask for a close-up. It had to be rigorously planned and designed to make sure that the components of set they filmed on Holy Island – such as the village gate, sat with our CG world. The mainland in the background in the real Holy island was too close for the story world so we had to push it back and get that sense of 1.5 miles distance.”
“Some of those angles are quite wide therefore, there's less emphasis on the detail, but then they would ask for a close-up. It had to be rigorously planned and designed to make sure that the components of set they filmed on Holy Island – such as the village gate, sat with our CG world. The mainland in the background in the real Holy island was too close for the story world so we had to push it back and get that sense of 1.5 miles distance.”
All of that work fed into the nighttime Causeway Chase, which is where the Alpha infected chases Spike and his Dad (Aaron Taylor-Johnson) back to the sanctuary of the island.
While production design, prosthetics and SFX created Boyle’s vision for the infected Union had creative input quite late in the process. “Danny decided he wanted to make the Alphas more menacing and less human. So we did a round of look dev, doing digital makeup effectively by graying that tongues and lips, creating bags under their eyes, reddening their eyes. Whereever, the larger infected appear in the film we applied that look by tracking those textures.”
An infrared look on some night time shots (ie where infected are feasting on a deer) was developed by Union with Boyle. “Not super complex, but I think really quite effective.”
Part two of the planned trilogy, 28 Years Later: The Bone Temple was shot back-to-back with this, is currently in post and due for release next January. It is directed by Nia DaCosta with photography by Sean Bobbitt.
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