Ikelite acrylic domes are injection molded specifically for underwater photography, and represent the finest optics in the industry. Domes are recommended for lenses 28mm and wider to preserve the full angle of coverage. Zoom lenses that do not focus to 12 inches (30cm) require a +4 diopter close-up lens. Accommodates lenses up to 4-inch (10.1cm) long and 3.3-inch (8.4cm) in diameter. Measure your lens or use Ikelite s Port Finder on their website to determine compatibility.