Metz Mecablitz 34 AF-3N - Manual (Page 12)

6. Flash synchronisation
6.3 Second curtain synchronisation (REAR)
Some cameras offer the facility of second shutter
curtain synchronisation.
With normal synchronisation, the flash is fired
precisely after the opening of the first shutter
curtain. When using slow shutter speeds, and
with moving objects, this would result in an
unnatural rendition of light traces.
With second curtain or rear curtain synchronisa-
tion, the flash is fired as the exposure is ending,
just before the second curtain covers the film again.
This makes the light trail behind the moving
objects instead of appearing in front of them, and
renders a more natural looking picture.
12
First curtain Second curtain