> Date: Thu, 18 Mar 1999 10:38:59 +0100 > From: Eertmans Nicolas <[EMAIL PROTECTED]> > Subject: RE: F100 and flash questions [v04.n304/17] [v04.n309/9] [v04.n310/13] > > >Flash duration varies depending on the individual flash > >and the amount of light required for correct exposure, > >but it's always brief enough to freeze almost anything. > > Well, at full power, a flash strobe is usually quite slow. Somewhere > around 1/150s. Flash duration rapidly decreases with power (around > 1/500s at 1/2 power, shorter than 1/10.000s for very slight flashes). > This effectively very slightly decreases the available guide number when > used with a high-speed sync cameras (1/250s or 1/300s), which is not a > big deal. > These numbers can't be right -- especially that full power duration is 1/150s. Many of Nikon's cameras give *full* sync at 1/250s shutter speed. The duration of full-power flash HAS to be shorter than that. The term "high-speed sync" explicitly refers to using flash at shutter speeds higher than the sync speed (e.g. higher than 1/250s or 1/300s for the F5). I don't have my speedlight manual with me, but I thought that the flash duration v. power tables were given in there. Chris -- Wilderness, wilderness... we scarely know what we mean _/ Christopher Somers by the term, though the sound of it draws all whose _/ Rise Technology nerves and emotions have not yet been irreparably _/ www.rise.com stunned, deadened, numbed by the caterwauling of _/--------------------------- commerce, the sweating scramble for profit and / Gallery: www.flash.net/~jboy domination. (Edward Abbey)