Spot Fill (appears in Subject)

The Spot Fill tool works like the standard fill light control, but adds circular area control for finer control of the effect with on-screen adjustments for size and position.
Fill: Extent to which the Light Color is added to the scene.
Radius: Size of the area outside which the blur operation is at full strength.
Spread: Threshold/softening region feathers the radius.
Falloff: Sets the median point between the Radius and Spread.
Light Color: Color used to illuminate shadow areas.
