"I didn't even think of it as art when I was doing it back then," Castro said during an online radio show in 2015.
In the 1970s, Castro began taking photos of San Francisco. He focused on the darker, sadder side of the city, like the then-crumbling amusement park at Ocean Beach, Playland at the Beach.
When punk came to San Francisco, Castro was there with his camera. He had taken pictures of bands before — most notably the Rolling Stones when they played Winterland in 1972. But the burgeoning punk scene inspired Castro, and he became a fixture at clubs like Mabuhay Gardens, Temple Beautiful and the Sound of Music.
Castro also focused his camera on the women in the male-dominated scene, taking just as many photos of female-fronted bands as he did of the male ones. Notable San Francisco bands he shot include the Avengers, the Mutants and VKTMS. He was also a big supporter of San Francisco's feminist punks Frightwig, documenting them through their decades-long career, which ended when drummer Cecelia Kuhn passed in 2017. Frightwig guitarist Mia Simmans said that the band "owes him a huge debt."
"[Castro] was a very dear and close friend. We refinished hardwood floors together for years, and I have eaten my lunch with him hundreds of times," Simmans said. "He has documented my life mdash; every episode, every band, every kid."
In recent years, Castro's been recognized for his work. A film he made featuring his photos of the Mabuhay Gardens was included in the San Francisco Punk Renaissance celebration in 2015 and later, he had a brick dedicated to him in the San Francisco Music Walk of Fame.
Friends of Castro's said he died of a heart attack Monday morning. There's been no announcements of any public memorials, but he can be remembered through all the work he posted online on his YouTube channel. But take note: he'd probably prefer you to see his work in person and not on a computer.
"It's not art. It's not photography if it's still on a screen," Castro said in 2015.