Some great examples of near/far clip regions and how they can influence the illumination and the shadows of a light source in Cinema 4d from Jamie Hamel-Smith in his latest quick tip.
The Near Clip and Far Clip features in Cinema 4D are pretty useful, but they can be slightly tricky to understand
Jamie provides an example showing how light clip regions can solve some problems in cinema 4D, when using light sources inside of geometry, such as a lamp or light bulb.
I think it would be important to note , that when creating renders physically as a goal (in general, not application specific), that is to say with a physical rendering engine, lights and materials; The ability to edit clip regions for the lights will break the physicality for the scene, and you may not want that at all.
check out the tutorial for Understanding Clip Regions for Light Sources in Cinema 4D here.