The EMWL Objective Lenses generate an inverted image, making it appear upside down. The Relay Lens corrects the inverted image and relays the image back to the focusing unit and sensor. The EMWL can be used without without the relay lens. Without the relay lens, you will have an inverted image, but the overall length of the EMWL will be approximately 6.5 inches (164.5mm) shorter.