Guest curated by O'Brian for the Art Gallery of Ontario in 2015, "Camera Atomica" was "the first substantial exhibition of nuclear photography to encompass the entire postwar period from the bombings of Hiroshima in 1945 to the triple meltdown at Fukushima Daiichi in 2011." The exhibition included over 200 works ranging from photographs taken by the United States government of atomic bomb tests to images of anti-nuclear protests on the streets of Toronto, to images by artists, to photos of the utilization of nuclear technology in medicine. In addition to addressing key issues in the nuclear era, "Camera Atomica" aimed to make visible the interconnections between nuclear technology and the photographic medium. One critic concluded that going to the show was “a civic duty.” Peter Galison wrote that "this remarkable show and catalogue promise to make clear that the age of the nucleus is also and always an age of the image."