Rear Curtain Sync
Canon
We’ve added Optimized Rear Curtain Sync capabilities with the ability for you to set the shutter speed at which rear curtain sync is engaged. The default setting is set at 1/100 second so any time you are at that shutter speed or slower, rear curtain sync will be engaged. You can adjust this setting (or turn it off) in the PocketWizard Utility under the Flash Tab.
We found in testing that the Canon system rear curtain sync timing is actually not at the precise end of the shutter opening, but actually slightly before (Fig 1). We have been able to improve on this timing to put the flash at the very end of the exposure (Fig 2).
You do not need to set anything on your flashes including Canon’s own Second-Curtain Sync button. Toggling the setting on the flash will not change the setting in the radio.
Nikon
Rear Curtain Sync in the Nikon system is simply controlled by the on-camera setting. When using a ControlTL capable radio, this setting is respected for enabling and disabling Rear Curtain Sync.
With a Nikon camera, the Rear Curtain Sync setting can be left enabled at any shutter speed; however, the Rear Curtain Sync functionality actually begins at 1/125th and slower shutter speeds. Refer to your camera's manual for more information.