Interview: Albert Maysles - Fab Four footage reveals the genius of the brothers who revolutionised documentary making

ALONG with his late brother, David, Albert Maysles (think "measles" with an "a") has been responsible for some of the most unforgettable documentaries ever made.

Although Albert – described by Jean Luc Godard as "the best American cameraman" – has been working solidly since David passed away in 1987, it is the films the Maysles directed together which have secured his lasting legacy.

These US filmmakers were pioneers of the groundbreaking and hugely influential genre known as direct cinema, which, in essence, was/is an attempt to capture true reality on film and simultaneously challenge the ethical responsibilities of filmmaker, subject and viewer. This was achieved, in large part, due to the advent in the late 1950s/early 1960s of lighter handheld cameras and mobile sound equipment. Using these tools, the Maysles moved away from more formal styles of documentary filmmaking, and into the up-close and intimate style we more or less take for granted today. Rather than featuring narration or interviews, Maysles's films revolve around the philosophy of being a reactive, almost passive filmmaker. They have been described as the deans of modern documentary, and it's no exaggeration to credit them with the evolution of – at its best – one of the most vital forms of communication and storytelling in existence.

Their seminal works include the 1969 film, Salesman, directed alongside their frequent collaborator Charlotte Zwerin, which offered a lacerating view of desperate US Bible salesmen, and (with Ellen Hoyde and Muffie Meyer) the immortal Grey Gardens (1975), which depicted – in astonishingly candid detail – the bizarrely decrepit lives of the two Edith Beales, an eccentric and reclusive mother and daughter duo closely related to Jacqueline Bouvier Kennedy Onassis. They also made significant contributions to the nascent rock cinema canon with Gimme Shelter (1970), their graphic account of the Rolling Stones' chaotic free concert at the Altamont Speedway, during which an audience member was stabbed to death by Hell's Angels supposedly acting as security. It has often been said that the anguish of Altamont signalled the death of the 1960s dream, and that the Maysles' film survived as its grisly epitaph.

Coincidentally, however, they were also fortunate to capture the moment when the 1960s suddenly exploded into optimistic bloom with the 1964 arrival of the Beatles on American shores in What's Happening! The Beatles in America. This little-seen gem receives its belated UK TV premiere next week in an Apple Corps edit re-titled The Beatles – the First US Visit.

"In February 1964 I got a phone call from Granada Television, asking if I would like to make a film of the Beatles," Maysles recalls. "They would be arriving at the airport in New York in two hours. I put my hand over the phone and turned to my brother and asked, 'Who are the Beatles, are they any good?' With a big smile, he responded that they were very good. We then both got on the phone, made our deal and rushed out to the airport in time to see the plane coming down, and started filming right away as they got off the plane. We got into their limousine and on to the Plaza Hotel. We were with them for the next week, day and night, camera in hand."

What followed was a tellingly intimate portrait of the Fab Four which is unlikely to be surpassed. "Little did we know we were recording history," says Maysles. Recording an event of such historical significance must be a documentarian's dream? "Yes, our dream came true and a dream which keeps repeating itself as I continue my 50-odd years of documentary filmmaking. One dream after another."

Given the gritty, intimate nature of his films, I ask how he dealt with his subjects during filming. Is it in the film's best interest for you to become quite close personally with them, or does he prefer to keep some kind of professional distance? "It's very important that you don't interfere with what's going on," he says. "At the same time you're not a fly on the wall where there's no intelligence or feeling to direct the camera. It's important to be in the thick of it. I find it easy to gain access to people first when we exchange glances, they catch something in my eyes that indicates that I'm confident and that I will be empathising with them. I'm sure that with the conviction that I can tell the truth, understand them and love them in a heart-to-heart relationship, not controlling, not asking questions, but fervently and respectfully listening, watching and reporting. I'm sure to get their cooperation. Besides, people would rather disclose than keep a secret."

Prior to breaking into film, Maysles studied and later taught psychology at Boston University. This, surely, must have given him a sensitivity towards people which has been useful throughout his filmmaking career? "Yes, with a social science background, I've always attempted to keep my prejudices out of my film work and to observe in a dispassionate fashion, without taking a point of view. Salesman, for example, is praised by the Catholic church as well as left-wingers. Both find truths that are self-evident."

A tireless campaigner on behalf of documentary filmmaking, Maysles curates a self-titled cinema institute in New York which exclusively screens documentaries from around the world. It also teaches local teenagers in the art of documentary.

Busy as ever at the age of 82, he is, among several other projects, currently working on an extended edit of footage he and his brother shot of Muhammad Ali in the late 1970s. So how does he explain the purpose and appeal of the style of filmmaking he pioneered and continues to endorse? "As a documentarian I happily place my fate and faith in reality. It is my caretaker, the provider of subjects, themes, experiences – all endowed with the power of truth and the romance of discovery. And the closer I adhere to reality the more honest and authentic my tales. After all, the knowledge of the real world is exactly what we need to better understand and therefore possibly to love one another. It's my way of making the world a better place."

• The Beatles – The First US Visit screens on BBC2 on Saturday, 5 September, 9:35pm.