What Is Slow Sync and How Is Is Used When Taking Photographs?

In photography ‘slow sync’ refers to a specific flash mode that allows slower than norman shutter speeds to be used when using flash to provide supplemental light to an image. Slow sync mode is used in low ambient light conditions where a photographer wants to capture a well lit subject against a well exposed, low lit background. In this situation the flash lights the subject in the foreground of the image, the shutter then remains open to correctly expose the low ambient light levels in the image background.