From the Adorama YouTube Channel:
Battery powered flashes are great for shooting portraits on location. There's plenty to choose from and they vary between small speedlights and bigger, more powerful monolights. In theory more power means more light and that's usually a good thing for location portraits but can a speedlight be used to light location portraits like a monolight? That's the question Gavin Hoey puts to the test in this video.
Gavin sets each flash the challenge of being used as a simple fill flash, creating dramatic skies by "over powering" the ambient light and finally getting some beautiful shallow depth of field portraits using HSS (high speed sync) flash. The results might surprise you!