When the projector is at a vertical angle to the screen, the projected image's top may become wider than the bottom or vice versa. At a horizontal angle, one side of the projected image will be wider than this other. This is called "keystoning".Keystone correction corrects this condition so the projected image has a normal shape. You should note, however, that keystone correction also compresses the image, which can cause some distortion and loss of image quality.If image quality is a priority, set the preset value of the "Keystone Correction" to "0", and position the projector so it is as perpendicular as possible to the screen.
