The Aquatica 4" Glass Dome Port is compatible for all Aquatica bayonet-style DLSR housings. This dome's small size makes it exceptionally well-suited for the close focusing fisheye lens. The reduced frontal footprint not only means that the photographer can move in closer to get the shot, but that it will be much easier for them to position their strobes for lighting the subject at such short distances.
The port is just 4” (100mm) in diameter and made of BK-7 grade mineral glass, which is finely grounded to the highest standard of precision. It’s coated with a superior Silicon Oxide coating (SiO2) on the convex surface and with a Broad Band Anti Reflective (BBAR) coating on the concave surface. The SiO2 coating is not only a more resistant type of coating than that used by most other manufacturers, but also has a 0.01% reflective index, providing unparallel light transmission among its competitor. Another important feature of SiO2 coating is that it’s a perfect match to the index of water, which naturally lowers reflections. Both the SiO2 and BBAR coatings not only prevent internal and external reflections but also protect the surface from scratches.
This port is best used with fisheye lenses only.