Flash Photography Using Remote (Off Camera) Flash Units (a video)
This podcast explores using an off-camera or remote flash unit to get a quality of light that is not possible with the built-in flash units.
The built-in flash in the typical SLR can be a remarkably effective tool, but in many situations it’s just not adaptable enough. External flash units give you a lot more control of the supplemental light that a flash provides. They also require a more in-depth understanding of light/contrast and how flash can help you control that.