The exact effect that I want isn't a realistic effect. It's from a first person point of view right before the person takes aim where the target is shown clearly in the scope. It's similar to the image below with the rifle and the scene. But instead of a dark lens which is realistic, a scoped image of the target would show. For example if there was a deer near the tree line, it would show a zoomed in version of the deer that's in the scene but too small to see without the scope.  Hopefully that didn't make things more confusing