For close-focus wide angle work, Zen Underwater is turning conventional 'big dome' wisdom on its ear with a 100mm (4") dome port. As an added bonus, the DP-100 offers welcome relief to the luggage bloat of dive photo travel and the ever increasing expense associated with checking large heavy camera systems. The DP-100 allows the photographer to get in close where a large dome just won't go for stunning close focus wide angle images. The DP-100 is constructed from hand crafted materials with an optically coated BK7 glass dome at its core. The surface of the dome element is coated with a magnesium fluoride broadband anti-reflective coating to minimize internal reflections from camera lenses, lettering on cameras, etc. which can be a problem in a bright ambient light situation. The exterior is treated with a proprietary scratch resistant coating to control lens flare. This coating yields an amazing 99.7%+ transmissive value for true distortion free images.