1. A method for providing a fog effect during computer animation of an image, comprising: with a fog effect module run by a processor of graphics system, determining a lighting value for each pixel of an image to be animated based on a location of each of the pixels relative to a light source; with the fog effect module, setting for each of the pixels a fade in start distance measured from a camera location at which to start adding fog, wherein the fade in start distances are each selected based on the determined lighting value associated with a corresponding one of the pixels; with the fog effect module, adding fog to the image including starting at the fade in start distances for each of the pixels; and with the graphics system, rendering the image using the fog-added pixels.