Jonas Mekas, Serpentine Gallery, London

"Just images, just images," murmurs the narrator of Jonas Mekas’ new 80 minute film Out-takes from the Life of a Happy Man (2012).

Some dated to New York of the 60s, images flutter one after the other into view: a green apple with a bite taken out it, positioned on the side of a swimming-pool, the sunlight both delicate and brilliant; a blonde girl wearing tight blue jeans on the subway; a man smoking and selling pretzels on the sidewalk; and, incongruously, the rushing of a waterfall. The white foam looks better on 16mm; indeed, everything looks better on 16mm.

Born in Lithuania in 1922, Mekas is a leading figure of the 20th century avant-garde. A poet, film-maker, artist, and founder of Anthology Film Archives, he emigrated to Brooklyn in 1949 after five years in displaced persons camps. His diaristic, fragmentary though flowing style of film-making is an exercise in “how to be true with the camera.” Rather than abstraction, he is interested in people - “what’s real, what’s there.”

Coinciding with seasons of his films at the BFI and Centre Pompidou, this exhibition draws on Mekas’ entire 60 year career. His Bolex transforms the ordinary into the iconoclastic, creating a grainy and beautiful world. Now Instagram offers a similar aesthetic to the digital generation, for whom images are easily captured and rendered antique-looking – a visual shorthand for authentic. In this sense, Mekas’ films and stills appear incredibly contemporary, as though they were made to be shared on social media.

His subject matter is likewise contemporary – autobiographical and intimate, lyrical but also heavy on the hipsterdom. This was a New York of the Beats, and, a decade later, the sexual revolution. Films such as The Dumpling Party (1971), in which John Lennon, Yoko Ono, and Andy Warhol eat dumplings in a basement apartment, are fun but problematic for the same reasons that Warhol is problematic. Other than demonstrating that he had a lot of cool and famous associates, what does it mean?

Mekas will turn 90 later this month, and remains prolific. It is his story as an artist in exile that is perhaps most fascinating. Idylls of Semeniskiai (1946) are poems that were written in a displaced persons camp, recalling his childhood in rural Lithuania. They evoke an atmosphere of “shimmering heat,” which is evident too in the later films, when the fields of home are replaced by Central Park.