The diffuser attaches to the front of the Quadra box. It offers a circular catchlight in the eyes of a subject, which is preferred by many photographers over a square reflection. The diffuser helps to radically change the way light falls on your subjects and surroundings. With the diffuser, you can minimize the effect of a direct on-camera flash and ensure images do not look washed out. With a softer, more even light spread, your portraits will have richer contrast, filled-in shadows, and better detail.