Photographer Andy Anderson often travels with a portable studio that he uses to make portraits in the field—a canvas structure of his own design with removable panels for shaping and diffusing natural light. He’s used it to photograph professional athletes, blues musicians, and gold miners. In the fall of 2009, Anderson set up his studio in a pasture at the Powers Ranch in Glenns Ferry, Idaho, and photographed his friend’s quarter horses and tack.

The results are published here for the first time.