Falloff Lighting offers the control and flexibility you need to properly light your scene. You can display the distance from the camera to the corners of the layers. Also, you can adjust the distance scale to account for the scale of objects in your scene. You can also control the intensity of light reflecting off an object and the gradual falloff as the distance from the light increases.'
This seems like another example of Digieffects revising and unbundling useful tools from earlier sets at a low price, like their recent Camera Mapper, which also stemmed from Buena Depth Cue. There's 2 tutorials available already too.
Click the tag Falloff for other options.