Ikelite are now shipping their WD-3 wide angle wet lens. Designed to minimise vignetting, the lens simply fits onto any Ikelite housing with a 3 inch diameter lens port. It can be removed and attached underwater.
The WD-3 wide angle dome retails at $300 in the U.S.A.
From Ikelite’s website
WD-3 Wide Angle Dome
The WD-3 Wide Angle Dome provides a wider angle of coverage underwater without the distorted edges or vignetting (dark shadows in the corners of the image) that are typically present when using a standard wide angle wet lens. At less than 6oz (168g), the WD-3 is also substantially lighter weight than the average wet lens and easier to use. The resulting image is crisp and clear edge-to-edge.
The WD-3 simply slides onto the standard port of the Ikelite housing— no modification to or replacement of the housing’s original port is necessary. The WD-3 can be removed and replaced underwater so there is no limit to the camera’s zoom or macro capabilities. Approximately 3/4 of the camera’s zoom range can be used with the dome in place (varies by camera model).
The conversion dome features a 0.75x conversion factor to correct for the refractive magnification of a flat port underwater. The WD-3 Wide Angle Dome is compatible with any Ikelite housing featuring a 3.0-inch diameter lens port. To check compatibility with Ikelite housings, please refer to the housing instruction manual or webpage.
MSRP $300 Product Number 6430.3