Roger Fenton. "Valley of the Shadow of Death" with cannonballs. 1855.

Roger Fenton. "Valley of the Shadow of Death" without cannonballs. 1855.

Writer and filmmaker Errol Morris, winner of an Academy Award for Best Documentary Feature, an Emmy, and the Grand Jury Prize at the Sundance Festival, drew on the Ransom Center’s photography collections for his most recent book, Believing is Seeing: Observations on the Mysteries of Photography, published by Penguin in September 2011.

Morris’s interest in the mysteries of photography grew around the debate over two nearly identical Roger Fenton photographs in the Ransom Center’s collections.  The photographs were taken in sequence in a place called the “Valley of the Shadow of Death” during the Crimean War.

In one photo, the road through the…