Flash sync speed
Flitssynchronisatiesnelheid · Light
The maximum shutter speed at which the entire sensor is exposed during a flash shot.
At faster shutter speeds only a slit of the sensor is open at any moment, causing a black band across the image. Most cameras have a sync speed of 1/200 to 1/250 sec. High Speed Sync (HSS) bypasses this by firing the flash at high frequency.
Tools that help with this: