The Zen Underwater WA-100 Pen Dome corrects one of the critical shortcoming of the Olympus PEN housings, the lack of a dome port for use with the M.Zuiko 9-18mm lens.  Wide angle lenses behind flat ports produce refractive magnification, radial distortion, and chromatic aberrations.  Each of these problems is solved by using an optically coated glass dome port, which retains the in air field of view of the Olympus M.ZUIKO DIGITAL ED 9–18mm f/4.0–5.6 lens and M.ZUIKO DIGITAL ED 14–42mm f/3.5–5.6L lenses.

 The Zen 100mm Pen Dome is an optically coated glass dome port that yields a 100-degree wide angle field of view with the Olympus M.Zuiko Digital ED 9-18mm and eliminates the severe pinchushion distortion exhibited by the standard Olympus flat port. This is a 25% increase in coverage and a dramatic increase in sharpness over the standard Olympus port!