Yongnuo YN560 - Rear-curtain Sync Technique; Reflection Flash Technique

6. Rear
-
curtain Sync
You can use slow shutter speeds to produce trailing smear for the object as
the flash
light will flash at the moment when the shutter is going to close; called rear-curtain sync
.
(The rear-curtain sync function needs support from the camera’s own settings;
you
should refer to the camera’s instruction
book on how to set this mode).
7. Reflection Flash
You can take photos by aiming the flash
light head at a wall or ceiling and using
the light reflected back from the ceiling or
wall to light the desired object, so that the
shade behind the object can be decreased
to get a more natural shooting effect.
If the wall or ceiling is too far, the
bounced light may be too weak to get
enough exposure.
The wall or ceiling should be even and white in order to get efficient
reflection; if the reflection surface is not white, color cast may appear in photo.