Full Frame Is 24x36mm Because a Leitz Engineer Doubled a Movie Frame in 1913

The short side of a full frame sensor is a silent-movie measurement. Cinema's full aperture ran about 24.89mm across the strip, from one row of perforations to the other, and when Oskar Barnack turned that film on its side in a workshop at Ernst Leitz in Wetzlar, that number became the height of a still photograph. The 36mm long side is two movie frames laid end to end with a millimeter or so shaved off. [Read More]