When the German photographer Wolfgang Tillmans was just a teenager, he would visit museums in Düsseldorf and Cologne on the weekends. With awe he studied the photo-based art of Gerhard Richter, Sigmar Polke, Robert Rauschenberg, and Andy Warhol. By 1988 he was hosting his own first solo exhibition, at Café Gnosa in Hamburg. Tillmans became known for his casual, snapshot-like portraits of friends, people such as the German-born fashion designer Lutz Huelle. “The viewer,” Tillmans has said, “should enter my work through their own eyes, and their own lives.” This exhibition examines the breadth of his career. —E.C.