Why did everyone start using 35 mm? This film—first used for cinema projections—became the international film gauge in 1909. A standard gauge with perforations allowed photographers to easily load and reload the same film in different kinds of cameras. Photographers still preferred different sized film for medium or large format prints, but 35 mm film was perfect for the popular small, portable cameras.
Rangefinder cameras revolutionized focusing. The rangefinder allowed photographers to measure the distance of a subject in order to correctly focus the lens. Early rangefinders required photographers to measure the range value before you could attach the correct lens. Later, coupled rangefinders showed two images—and allowed the photographer to turn a calibrated wheel until the two images focused into one.
