Flash of High Power
|A Flash of High Power is accomplished by many firings of a single flash unit and/or firing more units to get the total flash power required. Flash firings add at the square root of the of total number flash firings used. Example: Hue Candela makes the Lighting Strobe which consist of eight Vivitar 283s or 285s that are fired at one time. At full output power the output is 480 watt-seconds per firing. At four firings of the Lighting Strobe the total power for the film image is 2,000 watt seconds. The numbers work this way; 60 watt-seconds for 1 flash unit, one firing of Lighting Strobe equals 8 times 60 or 480 watt-seconds or +3 stops over one 60 watt-second flash unit, 2 Lighting Strobe firings equals 960 watt-seconds or +4 stops, and 4 Lighting Strobe firings equals 2,000 watt-seconds, or +5 stops, or equal to 2,000,000 watts for 1/1,000 of a second. Thus a Flash of High Power is created for cameras with very high f-stop.
Note! By moving the flash units closer by 0.500 times the last distance equals +2 stops for the new distance. Example 15 inches original distance subject to flash, at 7.5 inches +2 stops, at 3.75 inches +4 stops. At 0.707 times the last distance equals +1 stop for the new distance. Example 15 inches original distance subject to flash, at 10.6 inches +1 stops, at 7.5 inches +2 stops.
Caution the camera to subject distance has nothing to do with the lighting of the picture, only the image size on film.