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 30 cm require a 4 diopter close up lens accommodates lenses up to 4 inch 101 cm long and 33 inch 84 cm in diameter measure your lens or use ikelites port finder on their website to determine compatibility