How much light does your camera see? The aperture of your camera is its portal to the light in your scene (and without light, there are no pictures or video). Controlling the aperture is essential to getting the right amount of light on to your camera’s sensor to capture the best shots.
There’s another side to aperture as well. As you open the aperture wider, you can narrow the depth of field in your shot, blurring more of the frame outside of your immediate focus area. This is often a hallmark of the “DSLR video” look. Mastering aperture is critical to high-quality video and photos.