On Fri, Jul 2, 2010 at 4:53 PM, John Sessoms <[email protected]> wrote: > The K-10D and K-20D both allow you to set the on-board flash to trailing > curtain sync. How difficult would it be for them to make the hot-shoe also > fire on the trailing curtain when a non-dedicated "flash" is installed?
Very difficult unless certain assumptions about burn time are made, which won't be accurate. You need to fire the flash at just about exactly the burn time before the shutter closes for trailing curtain to work corectly. Most speedlights have a roughly 1ms full-power burn, but at low power levels it can be an order of magnitude shorter as output is normally controlled by burn duration rather than intensity. Olympus did allow this on some OM models, but it only worked because of the low sync speed of the camera's (1/60) so that even if the flash burn time was much shorter than the assumed ~1ms you don't get much exposure after the burn ends. This doesn't work so well with today's high sync speeds. -Adam -- 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.
