This 9.25” / 235 mm port is made of BK-7 grade mineral glass which is finely grounded to the highest standard of precision. It’s coated at no extra cost 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 competitors. 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.
As its name implies, the Megadome is large and exceptionally well suited for the full frame camera housing used by demanding photographers. Its size is meant to accommodate the most extreme ultra wide angle and fisheye lenses on the market today, and to extract the maximum optical performance from them underwater.
With such a large radius, it’s the ultimate dome port for taking over/under images. Water droplets shed faster on glass than they would on acrylic dome ports, and its very large diameter means that it is far easier to attain the required depth of field necessary to have both the underwater subject and the surface background in focus than it is with a smaller dome.
The rugged dome shade is integrated and its extended petals allow the housing to be placed face down, a useful characteristic when working on the camera housing. The neoprene cover protects the entire surface of the dome and is supplied with the port.
This 9.25” dome port will accept a wide range of lenses by using various extensions rings. The lens chart associated with your camera housing will inform you of the necessary and recommended accessories for using this dome port.