German mathematician who first suggested the idea of a portable camera obscura. The latter is a dark chamber, used for experiments in optics and generally considered to be a precursor to the modern camera. In 1572, Risner suggested that rather than a darkened room, a wooden hut would make a more useful camera obscura since it could be moved. He also edited a highly influential edition of writings by Alhazen (965-1039) and Witelo (c. 1230-c. 1275) on optics.
"Friedrich Risner." Science and Its Times: Understanding the Social Significance of Scientific Discovery. . Encyclopedia.com. (September 19, 2018). http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/friedrich-risner
"Friedrich Risner." Science and Its Times: Understanding the Social Significance of Scientific Discovery. . Retrieved September 19, 2018 from Encyclopedia.com: http://www.encyclopedia.com/science/encyclopedias-almanacs-transcripts-and-maps/friedrich-risner