Time:

Many of the women Luisa photographed—Oprah Winfrey, Hillary Clinton, Aretha Franklin, Serena Williams, among others—have been photographed throughout their careers by some of the greatest photographers in the world. And most photo shoots involve a photographer with multiple lighting assistants, production assistants and crews of helpers.

As Luisa told me in our interview, which you can read here, many of them were disarmed by her stripped-down, bare-bones process. The iPhone has become so ubiquitous in our culture, so essential to the way we are communicating, that our subjects, I think, were at first surprised that something so basic was being used for something as singular as a portrait for TIME.

These are wonderful photos of amazing women. That they were shot so quickly on something as “simple” as an iPhone (and three different models at that) shows the power of the device in the hands of an accomplished photographer.