For the optimum use of the lumens of your projector, you must be aware of the ambient light in your room. The ambient light affects the brightness, thus your viewing angle. Apart from ambient light the size of the room also matters. For example, 300 to 1000 ANSI lumens would be projected up to 60 inches of the images in the presence of ambient light in the room. The same lumens can project up to 100 inches of images in a large dark room.