Archived posting to the Leica Users Group, 2002/01/13
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>A flashbulb has an ON time that is measured in many tens of >miliseconds..... A ELectronic flash is tens of >microseconds.......different story... Right. Now think of a true strobe, rapidly flashing. That's how it works. Now...we can trigger the flash at any point in the first or second curtain's travel simply by adjusting time at which the synch contact closes, so the contact closes when the first curtain starts moving, the strobe flashes while the curtains are traveling and stops when the second curtain closes. The actual duration of curtain travel is the same for all speeds above, in the case of an M Leica, 1/50, therefore the flash can strobe for a fixed time, no need for that to change. The way TTL control works is to simply clip the duration of each pulse. I don't know what frequency Olympus uses but it's high enough that there's no banding. John Hicks jhicks31@bellsouth.net - -- To unsubscribe, see http://mejac.palo-alto.ca.us/leica-users/unsub.html