[tiemann@localhost blender-2.43]$ diff -u source/blender/render/intern/source/shadeoutput.c~ source/blender/render/intern/source/shadeoutput.c
--- source/blender/render/intern/source/shadeoutput.c~	2007-02-14 09:36:39.000000000 -0500
+++ source/blender/render/intern/source/shadeoutput.c	2007-04-30 04:41:30.000000000 -0400
@@ -1033,7 +1033,8 @@
 /* lampdistance and spot angle, writes in lv and dist */
 float lamp_get_visibility(LampRen *lar, float *co, float *lv, float *dist)
 {
-	if(lar->type==LA_SUN || lar->type==LA_HEMI) {
+	/* Special case where HEMI lamp distance of less than one means "no falloff at all".  */
+	if(lar->type==LA_SUN || (lar->type==LA_HEMI && lar->dist < 1)) {
 		*dist= 1.0f;
 		VECCOPY(lv, lar->vec);
 		return 1.0f;
@@ -1054,6 +1055,10 @@
 			else
 				visifac= 0.0f;
 		}
+		else if (lar->type==LA_HEMI) {
+			/* Let HEMI lamps decay just like docs say they do.  */
+			visifac= (lar->dist/(lar->dist+dist[0]));
+		}
 		else {
 			if(lar->mode & LA_QUAD) {
 				if(lar->ld1>0.0f)
[tiemann@localhost blender-2.43]$