The term is derived from
brands of widely marketed photographic leaf shutters manufactured from the early 1950s by two distinct, but now defunct German companies. (which made the
Prontor-S and
Prontor SV models, amongst others) and
Deckel (the
Synchro-Compur model, successor to the
Compound model). Both companies' brands,
Prontor (from 1953) and
Compur (from 1951), shared a common 1/8"-inch coaxial connector for shutter–flash synchronization. This convergence of design is not as coincidental as it might first appear, as the
Zeiss organisation held a significant shareholding in both of these companies prior to the introduction of the shared connector. By the 1950s, Gauthier were manufacturing up to 10,000
Prontor shutters daily. The Gauthier company's essence lives on as , which is a wholly owned subsidiary of . The Deckel company went bankrupt in 1994. ==References==