“I also have experienced what he was going through – having to compromise with reality, feeling lost and depressed even after attaining your dream. He was standing at a fork in the road and he had hesitations [about what to do next].”

Ann Hui’s Our Time Will Come named 2017’s best picture by Hong Kong Film Critics Society

Lost in the Fumes follows the radical localist, starting with his campaign to win a seat on Hong Kong’s Legislative Council. Things didn’t go according to the script when Leung was barred from the election because of his advocacy of independence for Hong Kong – a special administrative region of China since the end of British sovereignty over the territory in 1997. Nevertheless, Lam continued trailing him, camera in hand, going as far as Boston in the United States when he left Hong Kong for a respite from the furore over localism last year.

“It’s a relatively short period for a documentary, but within this time frame, he went through the cycle of ups and downs most politicians would experience in their entire career,” says Lam, who graduated last year from the University of Hong Kong with a degree in comparative literature and French.

Lam’s film depicts many of the recent big moments in Hong Kong politics, but it was Leung’s surprising candour and vulnerability that would leave the strongest impression on her.

Leung talks about his struggle with depression, and his doubts about his political beliefs and about the 2016 riot in Mong Kok, one of Hong Kong’s busiest districts, triggered by a police crackdown on unlicensed Chinese New Year street hawkers.

He also felt guilt when his childhood friend – whom he invited to join the Hong Kong Indigenous political party – was indicted for rioting, and he speaks of his fear of losing his integrity and becoming like the politicians he so despises.

Ranking every Hong Kong film released in 2017, from worst to best

Lam was initially “just Facebook friends” with Leung, but slowly got him to open up even in front of the camera. This she puts down to the approach she took to shooting her documentary: forming a relationship of trust with the subject and prioritising his authenticity over other factors, and truly getting to know him as a person.

Lam experimented with this approach after co-directing another documentary, Road Not Taken, in 2016, which followed student activist Popsy Hui and former Hong Kong student leader Billy Fung Jing-en.

Having started her film career as a campus reporter, she at first stood by the journalistic values and practices she was taught to follow – deliberately maintaining a distance between herself and this film’s two subjects and trying to be impartial.

“I wanted to talk about the confusion people had after the Occupy movement and these two characters fitted the framework I had,” she says, referring to the pro-democracy sit-ins that shut three major traffic arteries in Hong Kong for 79 days in autumn 2014. “But it felt like I was using other people’s stories and shaping them into the direction I wanted. Had I really understood them before I started filming them? I don’t think I did, and that is not fair.”

Lam felt acutely the power she had over the subjects in that film, and felt that, although it advanced her career, it did not give a true reflection of those involved.

Joshua Wong on Hong Kong human rights, those CIA rumours, and his Sundance winner Teenager vs Superpower

She felt the same sense of building her own career on others’ misfortune with the documentary about Leung, whose trial for riot and assault charges begins on Thursday; if convicted, he faces a maximum sentence of 10 years’ imprisonment.

“It felt very ironic when he confessed that he actually does not enjoy media attention and does not like being in front of the camera, but I was shooting him and would be following him for another few months,” says Lam.

This was why she abandoned her preconceptions and chose to let the story write itself, focusing on Leung instead of the political atmosphere that first caught her attention.

After completing the first cut in May 2016, she spent a further four months editing a second cut which focused on the emotions Leung was going through rather than the political events around him.

While Lost in the Fumes reveals an unknown side of Leung, it also received criticism for glorifying a controversial figure. “It came as a huge surprise because I felt like I was ruining his image instead,” says Lam. “For a politician to admit that he is not happy and he does not want to touch politics is to commit political suicide. Voters will never vote for you again.”

Hong Kong cinemas won’t show Occupy documentary Raise the Umbrellas, filmmaker Evans Chan fears

Though she did not set out to paint a positive image of Leung, Lam feels people who see her film will appreciate his honesty. “For anyone to reveal the rawest side of themselves sincerely, it has to be attractive because that is the core of who we are as humans,” she says.

As a young filmmaker, Lam faced challenges throughout the process of shooting the documentary. She was on a steep learning curve, and each day encountered a new technical problem. But in the end, the most taxing task was navigating the complicated relationship between herself as a filmmaker and the subject she was filming.

“Its exploitative nature makes me uncomfortable,” says Lam. “And it’s a problem you cannot solve. If it’s something technical, I can reshoot. If I don’t have enough money, I can raise funds. But this is something fundamental about documentary as a medium and it’s something other people will not understand.”

This is also why Lam has decided to take a break from documentary filmmaking and to try other genres instead in the near future.

Punched by police and shunned by cinemas, Occupy documentary maker Chan Tze-woon still a believer

While the films she has made so far – including a short film (Midnight in Mong Kok) on the Occupy protest in Mong Kok – all revolve around politics, Lam does not want to be typecast as a political documentary filmmaker and insists that Lost in the Fumes is not a political documentary.

Instead, she hopes audiences, regardless of their stance, can withhold their judgment and put themselves in Leung’s shoes.

Lost in the Fumes will be screened on January 24 at the Hong Kong Arts Centre, in Wan Chai, as part of the Hong Kong Independent Film Festival. Visit www.facebook.com/lostinthefumes for updates on its future screening schedule

Want more articles like this? Follow SCMP Film on Facebook