All new dome port system utilizing a new 4" radius dome and interchangeable mounting body lengths. Most lenses do not perform any better with a larger dome than with the exceptional 3" radius dome ports except for lenses marked as recommended in the port charts. Edge sharpness with either dome system may be enhanced by the addition of a +2 diopter close-up lens. Over-under photos may be easier with the larger dome. The #5510.22 has been optimized to operate with the Nikon 12-24mm zoom lens or Canon 10-22mm zoom lens. Addition of a +2 diopter close-up lens to the camera enhances corner sharpness.