All…I enjoyed reading all

All…I enjoyed reading all the comments and suggestions.  I, too, have a situation somewhat related to sunrise/-set.  I shot a (my second) wedding video–outside at a gorgeous site.  My "creative" side wants to end the video with a shot of the site (empty, of course) while the sun sets (shooting to the east, sun at my back) and the scene eventually goes dark (or black, perhaps).  I thought time-lapse would be a good technique, but I need some guidance/suggestions camera settings.  I did some shooting with the camera on "auto," and the camera tried to keep the scene "visible," and just got grainy.  I am shooting digital video (Sony).  Thank you.