Calling the eighteen photographic portfolios sampled in this midcareer retrospective “cantos” allows Richard Misrach to foreground the poetic intent of this enormous project. His aesthetic is deeply affected by political judgments, but it is ultimately concerned with dualisms like nature and culture, wilderness and civilization, situated in a thicket of references to the history of photography as an art form. The pictures in “Canto I: The Terrain,” 1981–84, set out this encounter from the first. A photograph of a canyon vista, for example, includes tourists contemplating the scene, and studies