Le Posographe exposure calculator. Exposure calculator with six pointers, all interlocked by complex linkages, the setting of each one affecting proportionally the others. Scales for outdoor subjects on one side. Month, time of day, subject type, aperture, sky, subject tone and lighting exposure time. Indoor subjects: floor colour, exposure time, position relative to window, sky area visible, lens aperture, external light. c. 1925. Manufactured by Kaufman, Puteaux, France; sold by J A Sinclair, London.