Barbara Hammer, an experimental filmmaker who began celebrating lesbian sexuality and history in her work in the 1970s, and who in her last years turned her battle against cancer into cinematic art, died on Saturday in her partner’s home in Manhattan. She was 79.

Florrie Burke, her partner, said the cause was endometrioid ovarian cancer.

Ms. Hammer’s filmmaking took a radical turn in 1970 when she came out as a lesbian. She was 30 and divorced from her husband when her first female lover helped her rediscover herself.

“Her leg touched my own and I felt this incredible rush — erotic rush — just through our knees, and I thought, ‘Oh, my God, I’ve never felt this for a woman before,’ ” she said in an oral history interview for the Smithsonian Archives of American Art last year. “And I decided right then I can act on this or ignore it. I decided to act on it.”