PosographAnalog mechanical computer for calculating six-variable functions. It computes the exposure time (Temps de Pose) for taking photographs indoors or out (depending on which side you use).  

Posograph

Analog mechanical computer for calculating six-variable functions. 
It computes the exposure time (Temps de Pose) for taking photographs indoors or out (depending on which side you use).  

  1. maschup posted this