--- a/src/scene.cc	Wed Mar 26 17:03:38 2008 +0100
+++ b/src/scene.cc	Fri Mar 28 00:53:20 2008 +0100
@@ -77,7 +77,7 @@
 
 Ray Camera::makeRay(Sample *samp)
 {
-	Vector3 dir = p + u*(0.5/f)*samp->x + v*(-0.5/f)*samp->y;
+	Vector3 dir = p + (u*samp->x - v*samp->y)*F;
 	dir.normalize();
 	return Ray(eye, dir);
 }