Jay Maisel is one of our greatest living photographers, known for his gorgeous, striking street photography and his eye for the art in the mundane. He is also, incidentally, New York’s most successful amateur real estate speculator. In 1966 he bought a six-story, 72-room bank building in the pre-gentrified Bowery. “The Bank” became his home, his studio, and a cabinet of curiosities housing his massive, ever-growing collection of found objects.

After half a century, Maisel — in his eighties and no longer able to afford the building’s upkeep — sold it, in 2015, for $55 million. It was a staggering financial coup but also the end of an era, as shown in a new documentary that premiered last night at Film Forum.

Directed by Maisel’s protege, the photographer Stephen Wilkes, Jay Myself follows Maisel through the most daunting of all house moves, as Maisel and his wife, daughter, and a platoon of professional movers try to edit and condense the detritus of a half-century of artistic life. The result is an elegy to a vanished New York and a fascinating tour of a never-to-be-replicated physical space that functioned as the cross-section of a brilliant and eccentric mind. The sold-out show was accompanied by an audience Q&A with Wilkes and Maisel.

The beautifully shot and sometimes funny documentary turns the tables on Maisel: The renowned photographer is now the subject — and he’s any documentarian’s ideal subject, an outrageous character with a lisp, fondness for cigars, and an old-school New York manner. Turning to find a camera observing him, he says, “You are a creepy little motherfucker.”

Maisel is endlessly fascinated by everyday objects the rest of us take for granted — brightly colored soda bottles; prosthetics; VHS cases; gears, springs, screws, and other mechanical thingamabobs. Admiring a smooth, oval-shaped rock, he says, “I mean you couldn’t build a rock this good. Although I have a friend who makes rocks.”

The documentary starts five months before the move-out date. The move costs “hundreds of thousands of dollars,” and requires 30 or 40 truckloads. One of the bewildered movers remarks to another, in Spanish, that Maisel tells him to throw out all the things that aren’t trash, and keep all the things that are.

“The Bank” itself is, of course, the perfect metaphor for Maisel’s love for the found object. When he bought 190 Bowery, also known as the Germania Bank Building, for a down-payment of $25,000, the Bowery was one of Manhattan’s most run-down neighborhoods. Even after moving in and renovating the 35,000-square-foot building, he left the graffiti-covered exterior untouched.

During the Q&A, Wilkes explained that he and the cinematographers wanted to capture the experience of being in the Bank, which was cavernously large but filled with winding corridors and thousands of shelves and drawers. “I wanted the camera to float through space,” Wilkes said.

Maisel answered questions about his relationship with his mentor Josef Albers, the German-born modernist painter who taught him art at Yale and influenced his love of color. “He did things on his own terms,” Maisel said, “and he liked to persuade you that he was very eclectic, but he wasn’t. It was his way or the highway. We had a lot of trouble together. He taught color and I listened to every word with bated breath,” but “we had completely different ideas about painting. His were obviously much more successful.”

There are two kinds of people, Maisel said: those who like photography and those who like photographing. He is the second. “We do not take pictures. We’re taken by pictures.”

Maisel misses the Bank, which was bought by the real estate developer Aby Rosen and turned into office and retail space. (The streetwear company Supreme is currently using the ground floor as a temporary home.)

“I love the movie,” Maisel said, but watching it “depresses the shit out of me.” Of course, the proceeds of selling the Bank allowed him to buy a $15 million townhouse in Cobble Hill. “I have a nice place,” he admitted. “People don’t shit on my door any more.”