Profoto recently put together a four video tutorial series starting off with the differences of on-camera and off-camera flash and many other things. It goes without saying that if the flash is off of your camera, then you have significantly more versatility with how you can place it in your scene where when it is tied down to the hot shoe, the flash only can bounce its output.
Photographer Jared Platt demonstrates the differences in a real life scenario when it comes to shooting portraits outside with the sun. Most folks don’t know this, but in direct sunlight is when you’re most recommended to use a flash. But besides that, off-camera flashes can also light a subject from various angles if you have lots of them around.
Profoto also talks about hard lighting vs soft lighting, on-location vs studio and a bare head vs an umbrella. The videos are in a series after the jump.