A Type 353 DuMont oscilloscope camera mount fitted with a Type 2620 Polaroid camera. The camera lens is an Alphax 75 mm, f1.9 model produced by the Wallensak-DuMont Group of Rochester U.S.A. These recording units were invaluable in recording wave forms and events viewed on oscilloscopes before the advent of oscilloscopes capable of digitizing an oscilloscope trace. Focus on the screen was achieved by manual adjustment while viewing through the monocular viewing port. A shutter could then be slid across the viewing port to prevent interfering light.
Various versions of the cameras were produced. Many had a binocular viewing port and later models had an electronically controlled camera shutter that would be triggered by an event that simultaneously produced a trace on the oscilloscope screen. With the version shown here, photographs could be easily obtained of repetitive waveforms or on a “catch-by guess” basis only for irregular pulses. Photographs were available almost immediately with the standard “instant” Polaroid films.
