fl. 1680s

German inventor whose box-sized camera obscuras provided a prototype for the box and reflex cameras that appeared at the advent of photography in the nineteenth century. Originally the camera obscura consisted of an entire room in which all light was shut off, except for a small hole at one end; thanks to innovations beginning with Friedrich Risner (d. 1580), however, they were small and portable by Zahn's time. Zahn, a monk from Würzburg, developed lenses of varying length for viewing scenes at a greater or lesser distance.