Judy Dater is an American photographer and feminist. She is perhaps best known for her 1974 photograph, Imogen and Twinka, featuring an elderly Imogen Cunningham, one of America's first women photographers, encountering a nymph in the woods of Yosemite. The nymph is the model Twinka Thiebaud.
Dater was born in 1941 in Hollywood and grew up in Los Angeles. She studied art there, before moving to San Francisco to take a photography course with Jack Welpott, whom she later married. In 1975, they published a joint work, titled Women and Other Visions. They were divorced by the early 1980s.
In 1964, Dater met Imogen Cunningham, whose life and work had greatly inspired her. In 1979, three years after Cunningham's death, she published Imogen Cunningham: A Portrait, containing interviews with many of Cunningham's contemporaries, and photos by both Dater and Cunningham. This book also contained the photo: Imogen and Twinka.
Judy Dater now lives in Berkeley, CA with her husband Jack B. von Euw.