By Iain Blair

Do you suffer from vertigo? Are you deathly afraid of heights? Does the thought of hanging by your fingertips over the void make you feel like throwing up? Then the new, nail-biting climbing film Free Solo, which won the Oscar for Best Documentary feature, might not be for you.

But if you enjoy an edge-of-your-seat thriller that allows you — thanks to truly awesome cinematography — to virtually “free solo” (climb a rock face without any safety gear) from the comfort of your own armchair, then you should rush to see this inspiring portrait of an athlete who challenges both his body and his beliefs on a quest to triumph over the impossible.

Jimmy Chin and E. Chai Vasarhelyi

Made by the award-winning husband-and-wife team of documentary filmmakers E. Chai Vasarhelyi and Jimmy Chin (a renowned photographer and mountaineer), it follows daredevil climber Alex Honnold as he prepares to tackle the greatest challenge of his career: a death-defying ascent of Yosemite’s famous 3,200-foot sheer rock face El Capitan — without any ropes, safety harness or assistance in a “free solo” climb. His meticulous preparation is complicated by his falling in love with a new girlfriend, Sanni.

I spoke with the filmmaking couple, whose credits include the acclaimed 2015 climbing epic Meru, about making the Nat Geo film, their love of post, and the Oscars.

Congratulations on your Oscar win. How important are Oscars to a film like this?
E. Chai Vasarhelyi (ECV): Incredibly important, as they bring so much attention to it and get it to a far wider audience than it might otherwise get. But, of course, we didn’t make this with awards in mind. You can’t think like that when you’re doing it, but we’re so grateful for the nomination.

This is not your typical climbing movie. Jimmy, you’re also an elite climber. What drives someone to do this, and what sort of film did you set out to make?
Jimmy Chin (JC): I think it’s the same thing as what makes us want to go to the moon, or why someone pushes themselves to the edge for their calling or passion: to see how far you can take it. That’s at the heart of this and the sort of film we set out to make, and what’s amazing about Alex and his story is just how far he’s come.

He was this very shy, sort of awkward kid who was scared of all kinds of things, and through his determination to face all his fears — whether it was simply hugging people or his dislike of vegetables — he’s gone through this huge transformation. Climbing like this was, I think, ultimately easier for him to conquer than some other stuff in his life. So we wanted to capture all of that, but also all the raw emotional moments that really engage an audience. It’s a film about this amazing climb, but it’s not just a climbing movie. That’s how we approached it.

Alex is also a friend of yours. How do you film a potentially fatal climb like this without exploiting it?
ECV: It was a big ethical question, even if a more extreme case of it than comes with every documentary. Did we even want to make this film? And, if so, how did we honor Alex and what he was trying to do without making it at all sensational. There are so many different ways to tell a story, and Alex had to trust us. Then there’s that existential ethical question at the center of it all — is he more likely to fall because we’re there filming it? That’s something we really had to wrestle with.

Alex thought more about his own mortality than anyone else, and he chooses every day to live a certain way and we were going to do everything in our power to mitigate the risk. So it was all about doing justice to the story and respecting Alex and every decision he makes, including the way he prepared so carefully for the climb.

How tough was the shoot?
ECV: It was very hard, even though we had a big team of elite climbers who were also great cameramen and trained for two years to do this.

JC: We had over 30 people on El Cap alone, including four cameramen on the wall, including myself, and most of us were very up high — around 2,000 feet. We used some very long lens cameras on the ground, as well as some remote rigs and drones and other equipment. But we knew that we were in situations where a simple mistake could be catastrophic. There were a lot of potential hazards, and the big thing for the crew was to never get distracted, which is so easy when you’re watching someone free solo up 3,000 feet in front of you. It was grueling and exhausting for everyone involved — super-intense, both physically and mentally. It’s hard to overstate what everyone went through to make this film.

Talk about re-teaming with Meru editor Bob Eisenhardt, who just won the ACE Eddie for this film. He told me it took over a year to edit.
ECV: It actually took over 18 months, partly because we had so much footage to look at and sort through. But I don’t think the sheer volume of footage was the main editing challenge. We were attracted to his story because there’s so much more to it than just the climb itself, and while we were all so prepared for that, we never anticipated him and Sanni falling in love. When that happened, you have to just go with it. We spent a lot of time trying stuff and figuring out how to marry that with the climb so that it played authentically to people very familiar with climbing as well as to people like me, who aren’t. It was all about a negotiation.

Where did you post?
ECV: All in New York, at our own post place called Little Monster Films, and then we did our sound work and mixing at Soundtrack with re-recording mixer Tommy Fleischman, and we also did some ADR work at C5 Inc.

Do you like the post process?
ECV: We love it, because you finally start pulling in all the layers — like the music and sound and VFX — and you see the film come to life and change as you go along. We also had the luxury of a long post schedule to play around with the material, and it’s so much fun.

Obviously, sound is very important, especially when Alex was out of range of wireless mics.
ECV: Having made a few films, we know just how important the sound is and we had a great sound recordist in the field and a great sound team. When you don’t climb with ropes, all the sounds are very subtle.

What VFX were involved?
JC: One of the big ones was trying to give you a sense of El Cap’s true scale. It’s so hard to get across just how big it is. We tried a lot of things and finally ended up getting access to Google Earth high-res satellite imagery, and we were able to 3D map that and then build out those moving, contextual shots, and all that stuff was done by Big Star.

Where did you do the DI, and how important was it to you?
JC: We did the DI at Company 3 with Stefan Sonnenfeld. It was very important as one of the big challenges was that we shot using a lot of different cameras, and so we had to work to get a consistent look and feel the whole way through, so you don’t pull people out of it at key moments. But we also didn’t want to create a stylized look to the footage. We wanted to keep it fairly naturalistic, and we worked hard on that.

Did the film turn out the way you hoped?
ECV: Yes, as we’d planned it so carefully — how to treat the climb, how you get to know Alex. This whole project took about four years, from start to finish. But Sanni was the big surprise.

What’s your view of Alex today?
JC: He’s an incredible person who did something no one else has ever done. It’s still hard to comprehend just how amazing this feat was.

What’s next? Another climbing film?
ECV: (Laughs) No. No more climbing for a while. It’s a documentary about conservation.