On Dec 26, 2006, at 10:19 AM, Gonz wrote: > That would mean that if you did this, then if the flash sync speed was > 1/250th, and you set the flash to second curtain sync, and you had > your > shutter set to 1/250th, then it would not work, because 1/250th before > the *second* curtain *release* was when the first curtain started to > release, i.e. the sensor was still not exposed. Maybe you meant > 1/250th > before the second curtain closed, i.e. right when the second > curtain was > about to be released. This would make sense. In that case, at this > speed, its equivalent to a regular first curtain sync flash.
Second curtain sync is irrelevant when you're setting an exposure time shorter than the minimum X-sync speed of the camera. The Pentax DSLRs have a minimum X-sync shutter setting of 1/180 second, which is comfortably longer than 1/250 second. The difference in timing means that the flash exposure will happen only 1/1000 second or so later than it would with first curtain timing at minimum X-sync speed of 1/180 sec. So it's pretty obvious that the special effects of second curtain sync are really for use with longer exposure times. The Sony R1, with a leaf shutter and second curtain sync available at all shutter settings, demonstrates this conclusively: the effect of second curtain sync is best seen in exposures of 1/30 and longer duration. Any shorter exposure than that and the differences are insignificant. Godfrey -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net
