10 Technologies Photographers Inherited From the Military

The zoom ring on a modern 70-200mm traces back to a viewfinder accessory the US Army Signal Corps clipped onto its 35mm combat movie cameras. Frank Back, the Austrian-born engineer who designed it, spent the war improving cameras and lenses for the Signal Corps and then turned the same optical trick into the first zoom lens that caught on. That kind of lineage runs through more of a modern kit than most people expect, and it runs shorter and less often than the retellings suggest. [Read Mo