"Leningrad-2" Photo exposure meter "Leningrad-2" A device with one measurement limit for brightness and two for illumination, having a miniature galvanometer with an intra-frame magnet and high sensitivity (deflection current of the galvanometer needle 25...30 μA). The readings of the galvanometer are transferred to the calculator using a tracking arrow connected to the calculator. The light receiver is a selenium photocell. 7*5*2 Sverdlovsk-2 Photoexposure meter "Sverdlovsk-2", front view. Produced in the 1970s. The simplest photoresistor lens had a field of view angle of 20° diagonally, which made it possible to determine the exposure based on a plot-important detail of the subject being photographed. The small diameter of the front lens of the photoresistor lens made it possible to determine the exposure through the optical system of the microscope. The selection of a plot-important detail of the subject was made using an optical viewfinder, in the field of view of which there was an illuminated frame-limiting frame.10,5*5*2,5