Side by Side is a documentary on camera technology. No, wait, come back! It’s much more interesting than that sounds.

We live in a transitional time for the cinema, between methods that sustained the art and industry for 100 years, and groundbreaking digital revolutions. A decade ago it would unthinkable to shoot a serious Hollywood feature on anything other than film stock; now, you have to be a special filmmaker with some clout to persuade the studios it’s worthwhile doing it that way — most stuff is shot on digital formats.

Side by Side is, primarily, about the debate between those who prefer the old film ways and those who embrace the digital future. There’s some other stuff about the history of the format and how we got from a place where shooting digitally was a joke for ultra-low-budget indies to a time when it’s the dominant filming method, but this is all framed in the context of, “should we really be abandoning film?” And, for cinephiles, it is a fascinating and complex debate — and, actually, for non-cinephiles: it’s the kind of debate you might find a little dull and for a niche audience, but could one day affect everyone who likes movies. It’s not just about pixel resolution or colour range or depth of field or how a filmmaker views dailies or edits the final product; it’s also about what constitutes a Film, what gives it that almost-indefinable big-screen quality; and about how we preserve these cultural artefacts going forward.

The significance of the debate is emphasised by the interviewees. Nearly every high-profile name who has at any time factored in the film vs. digital debate pops up, however briefly (renowned film advocate Christopher Nolan gets just a couple of comments; I think Peter Jackson is the only notable omission). Indeed, you can tell how significant the interviewees are just by looking at the poster — what more do you need to know? There are also others — producers, cinematographers, and so on — whose names you might not be familiar with, whose work you might not even know, but have insightful contributions to make. Presenter Keanu Reeves is not just a celebrity voiceover but also the primary (sole?) interviewer, and believe it or not he does a sterling job.

Side by Side is essential viewing for serious film fans. It’s a state-of-play piece that documents where things are right now and how we got here, while also serving as a record for the future of what people felt at this crucial tipping point. Film might be about to die out, and this film will tell you why that’s been allowed to happen.

This review is part of the 100 Films Advent Calendar 2013. Read more here.