[quote author=leeyiren link=topic=1155.msg5227#msg5227 date=1262266715]
to see the real image we need a screen. yet i notice most simulation dun include a screen. I request that someone create an simulation that is something like the one in this thread but add a screen that is adjustable so we can see how does adjusting the screen affect the image. thx 8) :D :) ;) :P :-*
[/quote]

I agree with your suggestion. Let me do some research on ways to show the sharpness of the image on the screen.

Good point.