Stephen Daldry, whose "Extremely Loud & Incredibly Close" retells the deadly events of Sept 11, 2001 through the eyes of a New York boy, believes there should be more films about the attacks and their consequences.
His movie, which was released in U.S. theatres in December, has divided critics and public opinion, and Daldry, who was presenting the picture at the Berlin film festival on Friday, conceded that some people believed it came out too soon.
The Briton said he approached "Extremely Loud" "with the honest awareness that some people would still find it was too soon, too much or too little, but in the end you have to trust your own instincts about what you think is appropriate."
The film stars Tom Hanks as a father killed in New York's World Trade Center on 9/11, Sandra Bullock as his widow, newcomer Thomas Horn as his son and Max von Sydow as a mysterious old man who becomes close to the traumatized boy.
The movie features reconstructions of people falling from the towers and the final phone messages left by the father who was trapped inside the buildings after the planes struck.
Based on Jonathan Safran Foer's 2005 novel of the same name, "Extremely Loud" is not the first feature film based on the 9/11 attacks.
But by focusing on the grief of a single American family, and in particular on the impact the attack had on a young and troubled boy, it has been seen by some as controversial.
Daldry said he consulted with families who lost relatives in the attacks and taken their comments to heart and mind.
The director of "Billy Elliot" and "The Reader" also expressed surprise at how few movies had been made about the attacks, which happened more than 10 years ago.
"It amazes me that more films aren't made about 9/11," he told reporters at in Berlin. "I don't just mean the stories in New York, I mean stories from around the world about not just what happened and why it happened or who it happened to, but the consequences of what happened and how those consequences still reverberate in all our lives.
"This particular story is focused on one family and the consequences for that one family.
"Do I think there should be (more) films made about the consequences of what happened in Iraq and what continues to happen in Afghanistan? Yes, I do think that's true."
Reviews of "Extremely Loud" have been middling to poor, with the Rolling Stone opining: "Solidly crafted, impeccably acted and self-important in the way that Oscar loves, 'Extremely Loud' is also incredibly close to exploitation."
Indeed, the movie was nominated for a best picture Academy Award to the surprise of some, while Swedish veteran von Sydow was shortlisted for a best supporting actor Oscar for his role as an old man who no longer talks.
His connection with the main character Oskar Schell, played by young newcomer Horn, is central to the film's plot as the boy goes on a seemingly impossible mission to find a lock he believes will reconnect him with his father.
Oskar appears to have some form of autism and, while bright and unable to stop talking, he also is an outcast who loses his one true friend when his father dies.
Horn told reporters that his only previous role had been as a grasshopper in a school play, but that he was now considering a career in acting.
Von Sydow was asked by Swedish reporters why he spent so little time in his native country. One magazine mischievously pondered whether he had been kidnapped.
"No Max von Sydow is not kidnapped, he has just chosen to live in France, simple as that," the 82-year-old said.
"Unfortunately the Swedes have a strange clause in their laws - you cannot have double citizenship. After years and years in France, I decided I should really be a French citizen."