The ring is a circular color band that surrounds the center of the source object. You set ring options on the Ring panel of the Lens Effects Flare dialog.
Specifies the overall size of the ring as a percentage of the overall frame and represents the diameter of the ring. The ring radius should be larger than the glow radius to make the lens flare look convincing. This parameter is separate from the overall size spinner in the Lens Flare Effects section of the dialog. This parameter can be animated.
Use radial, circular, transparency, and size gradients.