In 1983, Ms. Greenfield matriculated at Harvard, where her parents had studied, and where she encountered both Mr. Evers and a student body of immense privilege. While traveling around the world her junior year, studying film and anthropology, Ms. Greenfield met the pioneering French photographer Jean Rouch, who is credited with helping invent the style known as cinéma vérité, and after returning to Cambridge she changed her major to visual studies.

Ms. Greenfield then trained under Barbara Norfleet, who in the mid-1980s released “All the Right People,” a book of reportage photography focusing on East Coast elites. At the time, such creatures would mostly appear in staged portraits or respectfully edited party pictures, but Ms. Norfleet wanted to capture them and their rituals in the wild. “I realized the rich were, in many ways, this undercover group,” Ms. Greenfield said. “That’s hugely important, because they have so much influence.”

Encouraged by Mr. Evers, who had been hired at Columbia Pictures, Ms. Greenfield applied to film schools a few years after graduation, but she wasn’t admitted anywhere. She concentrated on still photography, earning assignments with National Geographic. Her first project, about a Mayan tribe in Mexico that her mother was studying, was spiked. But after rereading “Less Than Zero,” Bret Easton Ellis’s 1985 novel of California excess, she pursued an idea about her own native culture: a portfolio chronicling Crossroads and other deluxe schools, where students attended five-figure bar mitzvahs, drove Range Rovers and cavorted with celebrity progeny like Kate Hudson.

Ms. Greenfield turned the resulting images into her first monograph, “Fast Forward,” which earned her gallery representation and the attention of magazine photo editors. She traveled to the wealthy suburb of Edina, Minn., to record popular cliques enamored with Abercrombie & Fitch; and to Milan, where white teenage boys had co-opted the bandannas, baggy jeans and aesthetics of American gang culture. One fellow photographer told Ms. Greenfield that she ran the risk of pigeonholing herself, but she ultimately decided to “keep peeling back that onion,” she said.

Her pictures, relying on candy colors, awkward compositions and voyeuristic access, synced with the work of other rising photographers in the 1990s, including David LaChapelle and, a bit later on, Ryan McGinley. They also drew the attention of Sheila Nevins, the former HBO documentary president. In 2002, she hired Ms. Greenfield to make her first feature-length film, “Thin,” an unrelenting account of four patients at an eating-disorder treatment center in Coconut Creek, Fla.

To call any of Ms. Greenfield’s portrayals flattering would be inaccurate. (Ms. Siegel’s husband sued the director for defamation after the “The Queen of Versailles” was released, but the director won $750,000 in legal fees after an arbitrator ruled that everything in the film was true.) And she seems to have a knack for convincing people to be radically, unappealingly honest. Her subjects must find that cathartic. Many have agreed to sit with her repeatedly over the years, including for “Generation Wealth,” and Ms. Greenfield has stayed close with several of them, even those she’s captured in harsh light.