Using high speed flash sync to dim ambient light

…Hi my name is Ben Long and this week on the practicing photographer.…We going to do something really, counter intuitive.…I'm going to use my flash, to make the background in this scene darker.…And I know that sounds completely backwards but here's how it works.…Flash all flash have a sync speed, if…you watched my foundations of photography flash course you…should know this already, that there is certain shutter…speed on your camera that you cannot go past.…When you're using a flash, and this is because the shutter…on your camera is actually two curtains that open and close.…At faster shutter speeds there's actually just a little slit…of an opening that passes up and down the focal point.…

So there's not time where the shutter is completely,…open once you pass about a 200th of a second.…That means there's no time that you can fire a…flash into your scene and have it expose the entire frame.…So, on most cameras once you're using your flash, the camera, there's no way you…can dial it past a 200th of a second, sometimes it's a 160th of a second.…