Why use an off-camera flash? It gives you more lighting options. And much of the time, the light from an off-camera flash is just plain better. The image above was created with one flash to camera right.
Once the flash is off the camera, you can put it anywhere to get the light and shadows you want. This image was created with one flash high and to camera right, providing dramatic directional light. On-camera flash would not be nearly so effective.
For this image Image I wanted dark, dramatic shadows which were created with one flash far to camera left and almost even with the model.
For more even lighting, this portrait was created with two flashes, one to camera left and one high and to camera right. The flash to camera left was on a lower power setting, creating some shading and contouring of the face.
There are a lot of options for getting your flash off the camera and it will make a big difference in your photography.
Article Links: Off-Camera Flash Series
“How To” Series: Off-Camera Flash – Series Introduction
Some of the Best Off-Camera Flash Equipment
Radio Controlled Speedlites: Yongnuo YN600EX-RT vs Canon 600EX-RT
Light Modifiers (Softeners) for Speedlites
Putting Together a “Studio in a Backpack”
How To Set Up a Halo Softbox or Umbrella with an Off Camera Speedlite
Photo Shoot: Using a Halo Softbox with a Yongnuo Radio Controlled Flash System
Environmental Portraits and Off-Camera Flash, Part 1
Environmental Portraits and Off-Camera Flash, Part 2
Environmental Portraits and Off-Camera Flash, Part 3
AlienBees: High Quality, Economical Studio Lights
Using the Histogram to Check Studio Flash Exposures