Multiple Photos With The Microflash

® AN ELECTRONIC SEQUENCE TIMER, developed by the Air Technical Service Command at Wright Field, permits multiple exposures on a single film to be made with the Microflash. Developed by Captain C. H. Coles of the ATSC engineering division, the timer utilizes the constant rate of voltage increase across a linearly charged condenser to excite six amplifiers which are set to progressively decreased sensitivity. Each amplifier trips one Micro-flash lamp.

The interval between flashes is varied by simply turning dials on the sequencer panel, and the total time required for all six pictures can be adjusted between 0.6 second and 0.0003 second.

The photograph of Figure 2, which shows three exposures of a 0.50 caliber machine-gun bullet was timed by the electronic sequencer.

ASTC engineers found many uses for the Microflash during the war, in addition to bullet photography. Among

Figure 2. The electronic sequence timer and a battery of six Microflash units. Captain C. H. Coles of the Air Technical Service Command, who developed the timer, is shown at the controls.

these was the study of rupturing propeller blades. By using X-ray film, an f/2.5 night aerial camera lens, and a special developer, they have taken Microflash pictures successfully at distances of 40 to 50 feet from the lamp.

Figure 1. Three-exposure photograph of a 0.50 caliber machine-gun bullet.

Figure 1. Three-exposure photograph of a 0.50 caliber machine-gun bullet.

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