----- Original Message ----- From: <aghalide@xxxxxxx>
To: <rollei_list@xxxxxxxxxxxxx> Sent: Monday, December 07, 2009 4:49 PM Subject: [rollei_list] Re: Rolleiflash DisasterHarold Edgerton used flash to produce a stroboscopic effect. He was famous for his high-speed stop action photos. The high-speed photography was instantaneous. Flash bulbs are not instantaneous. They require what was called m or f synchronization. Camera shutters used to offer either x for instantaneous for electronic flash, or m or f delay which represented the time between when the shutter was fired and when the flash went off. You have the possibility of 3 delays for the flash when you click the shutter on older cameras. Only x has been retained, and they don't even call it x.
Ed Farber brought the electronic flash to the populace. He used a 510V battery to obtain enough voltage to produce the flash. The studio units utilizing low voltage battery packs were often very large and heavy and not practical. Eventually with the advent of the transistor to produce enought voltage the units were smaller and more practical. In some cases too small. He invented a high speed electronic flash in a company called Strobo Research in Rochester, NY. Which was bought by Graflex and permitted him to retire at an early age. rather than use a very large electronic flash to produce high speed result, Ed Farber (I edited his column about flash) used what I think was a rectifier to take the low voltage from the batteries and make it a high voltage. These rectifiers were very large. With the advent of the transister in 1959, Multiblitz in Germany did away with the rectifier and used transisters to increase the voltage from the battery pack to produce a practical hand-held electronic flash unit.
Ed Meyers There is some history of strobe flash at Graflex at: graflex.org/GHQ/GHQ-13-1.pdf A Google search for Kodatron will find a bunch of stuff. There is a brief biography of Dr. Harold Edgerton at: http://en.wikipedia.org/wiki/Harold_Eugene_EdgertonA search of Google Patents for Harold Edgerton will find the strobe patents.
-- Richard Knoppow Los Angeles, CA, USAdickburk@xxxxxxxxxxxxx
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