Canon EOS 5DS R Instruction Manual - Page 251

3 Setting the FlashN Shutter synchronization Normally, set this to [First-curtain synchronization] so that the flash fires immediately after the exposure starts. If [Second-curtain synchronization] is set, the flash will fire right before the shutter closes. When this is combined with a slow shutter speed, you can create a trail of light such as from car headlights at night with a more natural feel. With second-curtain synchronization, two flashes will be fired: once when you press the shutter button completely, and once immediately before the exposure ends. If [High-speed synchronization] is set, the flash can be used at all shutter speeds. This is convenient when you want to shoot with background blur (open aperture) in locations such as outdoors in daylight. Flash exposure compensation You can set flash exposure compensation up to ±3 stops in 1/3-stop increments. For details, refer to the Speedlite's instruction manual. Flash exposure bracketing While changing the flash output automatically, three shots will be taken. For details, refer to the instruction manual of a Speedlite equipped with flash exposure bracketing. 251