diff --git a/src/camera.js b/src/camera.js
index e5cafb3..4b861ea 100644
— a/src/camera.js
+++ b/src/camera.js
@@ -1036,7 +1036,9 @@ function update_ortho_scale(obj) {
     if (!m_obj_util.is_camera(obj))
         return;
 
-    if (render.cameras[0].type === exports.TYPE_ORTHO) {
+    var cams = render.cameras;
+
+    if (cams[0].type === exports.TYPE_ORTHO) {
         if (render.move_style === exports.MS_TARGET_CONTROLS) {
             var dir_dist = m_vec3.dist(render.trans, render.pivot);
             var new_scale = dir_dist / render.init_dist * 
@@ -1047,10 +1049,10 @@ function update_ortho_scale(obj) {
             var new_scale = dir_dist / render.init_dist * 
                         render.init_top;  
         } else
-            var new_scale = obj.render.cameras[0].top;
+            var new_scale = cams[0].top;
 
-        for (var i in obj.render.cameras) {
-            var cam = obj.render.cameras[i];
+        for (var i = 0; i < cams.length; i++) {
+            var cam = cams[i];
             cam.top = new_scale;
             set_projection(cam, cam.aspect);
         }