How to Use Second Curtain Sync on Your Canon EOS 6D
Using an external Speedlite on your Canon EOS 6D can create different effects, like those created with second curtain sync. When you use an external Speedlite, it fires when the shutter opens. This is all well and good when you’re photographing people or objects that are standing still.
However, when you use flash to photograph a moving object, the duration of the flash is much shorter than the shutter speed of the camera, especially when you’re photographing in dim conditions or at night. The movement of the object after the flash fires shows up as a blur of motion, but the blur is going away from the object.
When you enable second-curtain sync, the flash fires just before the shutter closes, creating a natural-looking motion trail that goes to the object instead of away from it. To enable second-curtain sync:
Navigate to the External Speedlite control menu.
Use the Multi-controller or Quick Control dial to highlight Flash Function Settings and press Set.
The Flash Function settings are displayed.
Use the Multi-controller or Quick Control dial to highlight First Shutter Synchronization, which is the default flash synchronization mode and then press Set.
The flash synchronization options are displayed.
Use the Multi-controller or Quick Control dial to highlight Second Shutter Synchronization and then press Set.
You’re now ready to photograph images using second-curtain synchronization.
There is also an option for High Speed Synchronization on this menu. When you choose High Speed Synchronization the flash will fire at all shutter speeds. This option is useful when you’re shooting in Aperture Priority mode using Fill Flash.