Two big terms that strobist photographers and anyone looking to get into flash photography will hear are flash duration and high speed sync. In lay man’s terms, flash duration will stop fast moving motion and high speed sync will deal with ambient lighting–but it gets even more complicated than that.
Dan over at Adorama created a video to show how this works. He demonstrates high speed sync and shows how at f1.2, you can get a very shallow depth of field in mid-day lighting while killing the ambient lighting and mixing it with strobe output to look natural.
Then he goes into the studio and shows how flash duration stops fast moving motion and how you need to have almost no ambient lighting in the scene for the best effect.
The video is after the jump.