Index: source/blender/nodes/intern/CMP_nodes/CMP_defocus.c
===================================================================
--- source/blender/nodes/intern/CMP_nodes/CMP_defocus.c	(revision 32424)
+++ source/blender/nodes/intern/CMP_nodes/CMP_defocus.c	(working copy)
@@ -280,8 +280,11 @@
 	// CoC radius buffer
 	crad = alloc_compbuf(img->x, img->y, CB_VAL, 1);
 
+	// additional scale for crad buffer for screen size awareness.
+	int screenWidth = img->x;
+	const float radDivider = 1024.0f;
 	// if 'no_zbuf' flag set (which is always set if input is not an image),
-	// values are instead interpreted directly as blur radius values
+	// values are instead interpreted directly as blur radius values	
 	if (no_zbuf) {
 		// to prevent *reaaallly* big radius values and impossible calculation times,
 		// limit the maximum to half the image width or height, whichever is smaller
@@ -289,7 +292,8 @@
 		unsigned int p;
 
 		for (p=0; p<(unsigned int)(img->x*img->y); p++) {
-			crad->rect[p] = zbuf ? (zbuf->rect[p]*nqd->scale) : inpval;
+			float rad = zbuf ? (zbuf->rect[p]*nqd->scale) : inpval;
+			crad->rect[p] = (rad/radDivider) * screenWidth;
 			// bug #5921, limit minimum
 			crad->rect[p] = MAX2(1e-5f, crad->rect[p]);
 			crad->rect[p] = MIN2(crad->rect[p], maxr);
@@ -299,7 +303,6 @@
 	}
 	else {
 		float wt;
-
 		// actual zbuffer.
 		// separate foreground from background CoC's
 		// then blur background and blend in again with foreground,
@@ -312,7 +315,8 @@
 			for (x=0; x<img->x; x++) {
 				unsigned int px = p + x;
 				float iZ = (zbuf->rect[px]==0.f) ? 0.f : (1.f/zbuf->rect[px]);
-				crad->rect[px] = 0.5f*(aperture*(dof_sp*(cam_invfdist - iZ) - 1.f));
+				float rad = 0.5f*(aperture*(dof_sp*(cam_invfdist - iZ) - 1.f));
+				crad->rect[px] = (rad/radDivider) * screenWidth;
 				if (crad->rect[px] <= 0.f) {
 					wts->rect[px] = 1.f;
 					crad->rect[px] = -crad->rect[px];