Even Steven Spielberg can feel blue after getting a bad review.

This is what documentary filmmaker Susan Lacy discovered when she turned the camera on the Oscar-winning director, spending 30 hours interviewing him for a feature-length movie about his storied career, Spielberg, which airs in Singapore on Sunday on HBO (StarHub TV Channel 601).

Speaking to The Straits Times in Los Angeles recently, Lacy, 68, says she believes Spielberg took it to heart when critics dismissed his first foray into serious drama, The Color Purple (1985), which was about the struggles of a Southern black woman in the early 1900s.

It stung when reviewers suggested he should stay in his lane and just keep making popcorn movies such as Jaws (1975), Raiders Of The Lost Ark (1981) and E.T. The Extra-Terrestrial (1982).

Producer Kathleen Kennedy "says in the film that it hurt his feelings", says Lacy, who also interviews directors Martin Scorsese, Francis Ford Coppola and Brian De Palma - Spielberg's friends and peers - along with actors he has worked with.

"I think that's a hard thing for him to talk about - there's a vulnerability there.

"But Schindler's List turned the tide," she says, referring to the 1993 Holocaust drama that won Spielberg the Best Director and Best Picture Oscars. The documentary explores Spielberg's reasons for making that film, the true story of a German businessman who saved the lives of thousands of Jews by deliberately employing them in his factories.

The director, now 70, had begun reconnecting with his Jewish heritage after his 1991 marriage to his second wife, actress Kate Capshaw, 63, with whom he has five children aged 20 to 29, along with a son, 32, from his marriage to actress Amy Irving.

But Spielberg "didn't make Schindler's List because he thought it was going to turn the tide - he did it because it was a movie that had to be made", Lacy says.

"He'd actually tried to get Martin Scorsese to make it - we didn't go there in the movie, but Marty gave it back to him and said, 'This is your tribe, not mine, and you have to make this movie.'

"This was a black-and-white movie about the Holocaust - he certainly did not expect it to have the impact that it did or to change the tide."

For her documentary, Lacy had unprecedented access to Spielberg, whom she says "is very shy about interviews and does very few".

As she spoke to him, the director revealed himself be a workaholic as well as a true master of his craft - despite the research she had done, the depth of his mastery still surprised her.

"Because he's never done a director's commentary on any of his DVDs, I was very impressed with how articulate he is about the actual craft of making movies and talking about what he was trying to do and why he did it.

"There's nothing unintentional about Steven's work. He can see ahead to how he's going to edit a movie and that's how he shoots the movie.

"Every actor I interviewed - from Daniel Day-Lewis to Jude Law to Leonardo DiCaprio to Matt Damon - that's what they were most impressed with, how much he understands of the process of film-making and how he sees ahead when he's shooting.

"There are very few film-makers that have that skill and it impressed everyone," says Lacy, who is married to landscape architect Halstead Welles and has one daughter.

"And you see that when he talks about it. I felt like I was having a masterclass in film-making."

The film-maker - who created the Emmy-winning American Masters documentary series (1987 to present) about the lives of cultural icons - also took pains to delve into Spielberg's psyche and "show that where he came from very much influenced the movies he made as a young man".

Her film examines the rough patches in his relationship with his father, which then informed the broken familial relationships in movies such as E.T.

"To hear him talk about the impact of his parents' divorce and that E.T. came out of a desire to fill the heart of a lonely child... really was quite extraordinary," she says.

•Spielberg airs in Singapore on HBO (StarHub TV Channel 601) on Sunday at 8am and 10pm. It will also stream on HBO on StarHub Go and HBO On Demand.