Added note about use of updateProjectionMatrix() after changing properties

docs/api/cameras/PerspectiveCamera.html

@@ -48,7 +48,11 @@ scene.add( camera );</code>
 
 
 		<h2>Properties</h2>
-		<div>See the base [page:Camera] class for common properties.</div>
+		<div>
+			See the base [page:Camera] class for common properties.<br>
+			Note that after making changes to most of these poperties you will have to call 
+			[page:PerspectiveCamera.updateProjectionMatrix .updateProjectionMatrix] for the changes to take effect. 
+		</div>
 
 		<h3>[property:Float aspect]</h3>
 		<div>Camera frustum aspect ratio, usually the canvas width / canvas height. Default is *1* (square canvas).</div>
@@ -103,9 +107,6 @@ scene.add( camera );</code>
 		<div>Gets or sets the zoom factor of the camera. Default is *1*.</div>
 
 
-
-
-
 		<h2>Methods</h2>
 		<div>See the base [page:Camera] class for common methods.</div>