Rear-Curtain Sync
Rear-curtain sync (also called second- or trailing-curtain sync) is the ability to time the flash pulse to just before the shutter closes rather than when it opens. This is usually used in combination with a longer exposure to gather ambient light while using the flash to freeze a main subject. With first-curtain slow sync, any motion trails captured by the ambient exposure appear to lead backwards from frozen subject. Rear-curtain makes it look right, but the downside is that it's much harder to get the timing right.
Again, the Pentax AF360FGZ and AF540FGZ can do this, as can all Metz models and the Sigma Super variant. Additionally, the Promaster 7500EDF and Sakar flashes can too.
