For effective second curtain sync actuation, all that is required is that the camera send a trigger signal to the flash at most .004 (1/250) second before the second curtain is released for its closing run. That's the typical longest electronic flash duration of a professional studio flash.
Nothing 'smart' is necessary in the flash at all. Godfrey On Oct 13, 2007, at 7:25 PM, Rick Womer wrote: > I'm not sure you're right... > > For effective second curtain synch, the flash needs to > fire =immediately= before the shutter closes. A > non-dedicated flash gets a signal at some point when > the flash is fully open, but does not know exactly > when the flash opened, or when it will close. For > second-curtain synch, the flash either needs to know > when the flash opened and the shutter speed, or needs > to get a signal a millisecond or so before the curtain > starts to close. Those are easily encoded so that > only a dedicated flash "knows", it would seem. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
