CULTUREPhotos: Delayed ExposureSam Wagstaff was Robert Mapplethorpe’s lover—and, says a new book, the forgotten patron who changed photography.by Fan Zhong11.03.141Robert Mapplethorpe and Sam Wagstaff, Arles, France, 1981. Photograph by Teresa Engle.2Sam Wagstaff’s Self-Portraits, 1973. Courtesy of the Getty Research Institute, Los Angeles, California.3Wagstaff in his apartment at Lafayette Towers, Detroit, 1970. Photograph by Enrico Natali.4Wagstaff at an Andy Warhol opening at Castelli Gallery, New York, 1964. Photograph by Billy Name.