GEOFF BENNETT: Robert Oppenheimer was one of this country's greatest scientists, father of the atomic bomb, a victim of the McCarthy witch-hunts, one complicated and fascinating man.

And he's now the subject of a new film by director Christopher Nolan.

Jeffrey Brown spoke to Nolan earlier this week for our arts and culture series, Canvas.

JEFFREY BROWN: Played by actor Cillian Murphy, Robert Oppenheimer comes to very large life in a film that is star-studded and action-packed.

But for director Christopher Nolan, it was the internal human conflict at its core that first grabbed him.

CHRISTOPHER NOLAN, Director, "Oppenheimer": It's genuinely the most dramatic story I know of, that I have ever encountered, either fiction or real life.

So, to me, taking on this person who changed the world irrevocably, I really warmed to the challenge of trying to jump into his head.

JEFFREY BROWN: I understand you even wrote the script in the first person?

CHRISTOPHER NOLAN: Instead of saying, Oppenheimer comes into the room, sits down at his desk, it says: I came into the room.

I sat down at my desk.

I felt that, that way, we'd be on a journey with Oppenheimer's story towards understanding, rather than judgment.

JEFFREY BROWN: Nolan based his drama on "American Prometheus," the 2006 Pulitzer Prize-winning biography by Kai Bird and Martin Sherwin, highlighting the ethical choices that played out in the very real time of World War II, with unknowable consequences on the ground and in the atmosphere, here between Oppenheimer and Albert Einstein.

TOM CONTI, Actor: What do you take it to mean?

CILLIAN MURPHY, Actor: Neutrons smash into nucleus, releasing neutrons to smash into other nuclei, criticality, point of no return, massive explosive force.

But, this time, the chain reaction doesn't stop.

TOM CONTI: It would ignite the atmosphere.

CILLIAN MURPHY: If we detonate an atomic device, we might start a chain reaction that destroys the world.

CHRISTOPHER NOLAN: I wanted to put the audience in the position of scientists asked by their government, by the military to help in a race against the Nazis to unleash the power of the atom.

And that's where the ethics come in, is in a situation where you truly have no choice, because you can't allow the Nazis to have a nuclear bomb, or be the first to have a nuclear bomb.

What then are your responsibilities as a scientist for something that was necessary and consequences that are, whether unintended or not, perhaps inevitable?

But in bringing this thing into the world, it raises all kinds of thorny questions about the responsibility of the creators for the technology that they unleash on the world.

JEFFREY BROWN: At 52, the British-born, L.A.-based Nolan is a powerhouse in his world, with blockbuster hits like "Inception" and "Interstellar" that bend time and space, "The Dark Knight" trilogy that reimagined the Batman superhero classic, and the historical epic "Dunkirk."

His films have grossed some $5 billion worldwide.

In "Oppenheimer," he took on new cinematic challenges, foregoing computer generated imagery, filming all the effects, using newly developed black and white, as well as color IMAX film, even in extreme closeups of characters faces.

The look and experience you're giving us, are they as important to you as the story, or do they somehow go hand in hand?

CHRISTOPHER NOLAN: Well, to me, they absolutely go hand in hand.

Cinema is this fusion of sound, images, music, humanity, shift in perspective, from the subjective to the objective.

I like to shoot celluloid film because it's still the closest analogy to the way the eye sees.

It's the highest-quality imaging format if you're shooting large format film.

So, even when it came to things like Oppenheimer's visualizations of atoms, the quantum world, and the thread of that that had to run through to its ultimate expression in the atomic bomb itself, I wanted those to be analog.

I wanted those to be real things we photographed.

JEFFREY BROWN: The first atomic bombs were dropped on Hiroshima and Nagasaki in August 1945, ending the war, though debate has continued whether Japan was already set to surrender.

The final death toll, uncertain as well, was at least 200,000.

Oppenheimer was left a public hero, a world-famous figure, but one racked with doubts about what he and his colleagues had done.

He would argue against the creation of the even more powerful hydrogen bomb and, amid the toxic Cold War brew of the 1950s, see his loyalty challenged, and, in a final humiliation, have his security clearance revoked.

Nolan is well aware of contemporary resonances, including the advent of A.I., a potentially world-changing technology unleashed without an understanding of potential consequences.

Do you worry that history is repeating itself?

CHRISTOPHER NOLAN: I take some comfort in learning that the leading A.I.

researchers literally refer to this moment right now as their Oppenheimer moment.

They're looking to his story for some kind of guidance about the role and responsibility of the creator of a piece of technology.

But, of course, as a filmmaker, not as a documentary maker, and not as a politician, I'm making a dramatic experience for the audience.

I'm trying to give them a thrill ride.

It's weird to use the word entertainment in relation to a story that's so serious, but entertainment in cinema is about engagement with a story.

And my job as a filmmaker is to -- is to pull the audience in for this very, very dramatic story.

And I think it raises a lot of relevant and troubling questions.

But it doesn't provide any easy answers.

JEFFREY BROWN: "Oppenheimer" is a -- it's a huge story.

It's a hugely important story.

It's a three-hour film.

You're an ambitious storyteller, filmmaker, an ambitious man?

CHRISTOPHER NOLAN: The thing I love about the movies, the thing I love about the cinema screen is, movies can literally be anything, any kind of story.

And, certainly, there's always been an understanding in the history of movies that this kind of story can be told on this scale for an audience.

Am I ambitious to sort of go ahead and do that?

I mean, yes, certainly.

But, also, history is on my side, in terms of, there are a lot of great examples of movies that we love that are more serious, do present a different type of entertainment.

It's a tricky word, as I say.

I prefer to say engagement.

But that's what we're doing.

We're telling a very big, very important story using the tools to put it on the biggest screen possible.

JEFFREY BROWN: Robert Oppenheimer died in 1967 at age 62.

Christopher Nolan is now telling his story in theaters worldwide.

For the "PBS NewsHour," I'm Jeffrey Brown in New York.