Twin-lens reflexes bearing the Minolta name had been offered as early as 1937, starting with the Minoltaflex (I). However, by the mid-1950s, the Japanese TLR market had become quite crowded. The Minolta Autocord series was an effort by Chiyoda Kogaku Seiko, K.K. to compete in the premium-quality segment of the TLR market. The Autocord series went through a large number of minor variations during its lifespan between 1955 and 1966—at least 17, by one count. All shared a number of desirable features: crank film advance with automatic shutter cocking and frame counting; a highly regarded Tessar-type 4-element Rokkor f/3.5 lens; slow shutter speeds, down to 1 second; self timer (some models); and an override button, allowing the advance crank to rotate backwards and cock the shutter without advancing the film, permitting double exposures. Early Optiper shutters only had speeds to 1/400 sec., but this was increased to 1/500 in later versions.
