Local filmmaker Stephanie J. Castillo has thrown a bit of a curveball to fans with her latest project, “Thomas Chapin, Night Bird Song.” After decades of focusing on stories either based in Hawaii or highly relevant to those living here, she spent extended periods over the last four years on the East Coast and in Europe researching the life and music of alto saxophone and flute virtuoso Thomas Chapin.

Chapin died in 1998 at the age of 40 from leukemia after spending much of the ’80s and ’90s in New York, where, according to the film’s website, his “passionate life and incandescent music remain unforgettable to fans who knew him and musicians who played with him.” His following extended to Europe, where he toured multiple times.

Chapin was also Castillo’s brother-in-law after the musician married her sister three months before his death.

Castillo, 67, is a regional Emmy Award-winning filmmaker who made her directorial debut with “Simple Courage,” the story of Hawaii’s leprosy epidemic in the late 19th century and Belgian priest Damien de Veuster, now a Catholic saint, who treated stricken patients at Kalaupapa, Molokai. Over the years she also completed films on Filipino-Americans who served in the U.S. Army (“An Untold Triumph”), the culture of cockfighting in America (“Cockfighters: The Interviews”) and a biographical look at her own mother, a war bride who left the Philippines with her soldier husband for a new life in Hawaii (“Strange Land”).

In 2010, after three decades of living on Oahu, Castillo moved back to her home island of Kauai to take care of her ailing mother. She considered herself retired from filmmaking and had taken a teaching job at Kauai Community College before deciding to come back and make one more film.

“I just kept thinking about this film and how it should be made,” she said. “I knew he deserved a film, and more importantly, the world didn’t know him because he died too soon. He was a great musician and is worthy to be known. He’s left his mark.”

More than 50 people showed up to watch preview clips of the film Jan. 4 in Chinatown. Castillo said most did not appear to be typical jazz fans, which was an encouraging sign in gauging interest in the project. She sat down with the Honolulu Star-Advertiser a few days later at the Honolulu Design Center to talk about her latest project.

Question: How much has the filmmaking process changed for you since your first documentary?

Answer: I started in 1988, and I made my first documentary with Hawaii Public Television and won an Emmy in 1993. Thirty years ago there were so few filmmakers in this town. I (raised) $500,000, and a huge chunk came from the 1991-92 Hawaii state Legislature, which you can’t do today. I got $200,000 from the state, and I got $93,000 from the federal government through a humanities grant.

Q: Do you adapt to change well?

A: You have to. I went from raising $500,000 on my first film to about $200,000 for this last one. The realities are so stark. I did my executive M.B.A. at UH in 2000 because I wanted to deal with the issues I was running into. So I went part time, got the M.B.A., and it gave me an incredible leg up in the sense that I can relate to the business world and relate my art. It’s been extremely helpful.

Q: As a filmmaker based in Hawaii, what led you to the East Coast and Thomas Chapin?

A: I think it’s easy to assume it’s because he was family. But as a journalist and a filmmaker, it has to be a great story. When he died his obituary was in The New York Times with a big picture. Also, the day I was reading the obituary with my sister, we were in the car, and NPR Boston was playing a tribute at the time. And I thought, “He’s somebody!” I had no clue!

Years later I flew to New York and interviewed 10 people he was close to. I got 10 different pieces of the pie, so that’s how I knew there was a story there.

Q: What was the filming process like?

A: I made the film I made based on interviews with 47 people. I found while doing my research, nobody had the whole story. I kept going until I felt I had a complete enough of a pie of principals who could tell really great stories about Thomas.

I started filming in June 2013 in New York City, Brooklyn and Hartford. Then I did another couple fundraisers to shoot a second round in New York City, and then another round to go film in Europe. I planted myself in England for three months to arrange the shooting I would do.

Q: What will this film do for Thomas’ legacy?

A: Most likely, there will never be another film made about him quite like this. The impetus for me was his compelling story.