Subjects in Motion - Slow-sync Flash

Slow-sync Flash

Using flash during a long exposure can produce interesting effects, producing a sharp flash-lit image combined with a  blurred ambient one.

Determine what constitutes a good daylight exposure first, and stop down by -1 to -1.5 stops to subdue the background, then adjust the flash (by setting the EV compensation to -1, for starters, or try different manual levels) until you have a pleasing balance between subject and background illumination.

If you can set your camera to rear curtain sync, then do so: the flash will fire at the end of the exposure rather than at the start, resulting in a more natural- looking blur which seems to follow, rather than precede, the subject. In this image, daylight is the junior partner and provides fill lighting for the flash.

How To Shoot... Motion Pictures - Slow-sync flash