THE last time I talked with Tim Hetherington was in the Libyan city of Benghazi.

A few weeks later he was dead, killed by shrapnel in another Libyan city, Misrata. Libya was in the throes of its revolution to overthrow the regime of Muammar al Gaddafi and the world's war correspondents - myself among them - had come to witness that bloody process.

It was April 20, 2011, when Hetherington died, with colleague Chris Hondros. In that same attack another photojournalist, Guy Martin, was severely wounded - a mortar round from the sky killing and maiming some of the most talented photographers of war in recent years.

Watching the opening scenes of Which Way Is The Front Line From Here? - The Life And Time Of Tim Hetherington is an eerie experience. Smiling, joking, the journalists film each other, the refrains of the Bee Gees' How Deep Is Your Love coming from the car radio in gentle discord with the shell-smashed streets through which they drive to their deaths.

"It's kind of strange doing a job and you're going out looking for fighting," Hetherington observes later in the film, a comment from part of an interview made years earlier after he and fellow photojournalist, James Brabazon, trudged for months through the West African rainforest with Liberian rebels. The two cameramen stayed with the fighters until they eventually besieged the capital Monrovia in 2004 before overthrowing dictator Charles Taylor.

The footage and still images Hetherington and Brabazon took during that epic assignment are still among the most powerful images of war in recent times that I have seen. Even back then, as Hetherington was finding his metier as a war photographer, it was typical of him - as depicted in the new film - that he once placed himself at risk of being shot by intervening to prevent the execution of a Liberian medic accused by the rebels of being a spy.

That moment, filmed by Brabazon, is one of many heart-stopping snapshots in Which Way, itself made by another of Hetherington's journalist film-making collaborators, Sebastian Junger. Hetherington and Junger worked together on the 2010 Afghanistan war documentary Restrepo, which was nominated for an Academy Award.

Before my final encounter with Hetherington in Benghazi, our paths previously crossed in Afghanistan's Korengal Valley when he was filming Restrepo. I had spent some weeks with a US Army air ambulance unit flying wounded out from the frontlines around Restrepo and the other firebases there, and remember thinking what courage and determination it must have taken for Hetherington and Junger to return time and again over the course of a year to document the lives of a single unit of ordinary American soldiers in one of Afghanistan's most volatile hotspots.

Some of the footage shot in Restrepo is deployed again by Junger in this touching tribute to his late friend. Indeed, so affected was Junger by Hetherington's death that not only was he moved to make Which Way but he has given up frontline war reporting.

Tall, rangy and larger than life, Hetherington read English Literature at Oxford, and was as articulate and eloquent with words as he was with photographic stills and moving images. This comes across frequently in the film. So too does his bravery and resourcefulness. Writing an obituary of Hetherington for our sister paper The Herald following his death in 2011, I commented on his extraordinary ability for getting into places, people and the heart of a story in a way most of his peers shuddered at the thought of.

"Photography made me free from a kind of destructive tendency that I guess I had inside myself … I could channel my energy somewhere," Hetherington explains in one of Which Way's many interview segments with him carried out over the years of his all-too-brief career. "At the root of my work is really this whole idea of intimacy," he explains in one scene, as he is filmed taking pictures of African schoolchildren with his Rolleiflex large format camera cradled in his hands. This is a camera, he says, that allows him to look down into the lens rather than directly at the subject, making for a different kind of visual relationship.

One of the great strengths of Which Way is its own degree of intimacy. In cameo glimpses we see the "real" Hetherington - a different kind of person from the dashing war cameraman. In one moment we see a boyfriend talking about the dangers of his work with his American-Somali girlfriend, Idil Ibrahim; in another, a doting son giving his father a peck on the cheek as he shows his parents a photo album.

Some reviewers have said Which Way is perhaps "a bit more solemn and funereal than necessary" and suffers "from some unfortunately sentimental choices in music". Perhaps there is a grain of truth in this, but only a grain. Overall, Which Way is powerful, gripping, revealing, and a tremendously accurate insight into what makes the war photographer and reporter tick.

On a purely personal level, I found it profoundly scary. Time and again watching the situations Hetherington confronts I was reminded of my own many close calls and other friends lost in the line of work. "There comes a point that it just is your reality and stops becoming weird and different," explains James Brabazon, talking of what it is like to be under fire. "It's just what you are living and breathing at that moment."

Tim Hetherington knew that and, yes, he lived for the moment. But his work provides a longer-term legacy, as will this tribute. It is a documentary about a passionate, talented and caring man as well as a consummate journalist. It is not to be missed.

Which Way Is the Front Line From Here? is in selected cinemas and on iTunes from Friday, and is out on DVD on October 21