The 6D does not come with a built-in flash, but you may find yourself in a situation where you’ll want to use an external flash unit. Any Canon flash will provide enough light to capture an average scene.
Higher-end flashes will provide you such features as wireless triggering, high-speed sync, and coverage for ultra-wide-angle lenses. Although the 6D is an advanced camera, you don’t have to invest in a top-of-the-line flash, especially if you don’t use flash frequently. You might find that a moderate-range flash, such as the 580EX II or 480EX II, is more than adequate for your needs (Figure 7.12).