Aw- come-on, that would make it much too easy. The falloff dials are using some value other than the screen distance units used by the translation dials. It works pretty well, you just gotta find the range. I've not played with it enough to explain a relationship between the distance and the value on the dial. I generally set the start and end values the same, and adjust them until the subject pops into ,or out of, the light pattern. From there, you can then back the two values off to create the actual falloff effect range. Here are some values that ought to get you in the ballpark: Oh yeah, because you cannot see the effect until rendered, finding that magic starting point requires a lot of guess&render, tweak&render, nudge&render, etc.