Built in flash techniques: 06. Second curtain flash
In its default set-up a flash will fire at the beginning of the exposure.
On many occasions this is fine, but if you are shooting a moving subject and using a shutter speed that doesn’t freeze it, there will be a ghostly image of the subject visible where it moved after the flash fired. It can look as if the subject is moving backwards.
However, if the flash is set to second-curtain mode, it will fire at the end of the exposure and the blurred movement will be seen behind the subject giving a greater sense of speed and a more natural looking result.
Second-curtain flash is often combined with slow-sync to accentuate movement and create dynamic images.
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