How to Use external Speedlite controls on the Canon 5D
Bruce Dorn from Canon breaks down the exposure and Speedlite controls on the Canon 5D Mark II. His explanations are especially helpful as he gives certain shooting scenarios in which tweaking these settings will improve your overall image quality.
Explorer of Light Bruce Dorn takes you step-by-step through EOS camera's External Flash Functions menu in this educational video, and through the EOS Wireless Settings menu, such as how to set flash ratios from your camera.
For more information on Speedlites, visit Canon's Speedlite Tip Series.