HD-6600 Pro Super Quality 0.66x Wide Angle Lens 37mm Mounting ThreadIn designing this lens we successfully controlled the color aberration and distortion of picture image at the least, and could reach to the highest resolution power of *350-line/mm at center.Mounting threads is 37mm.* MTF 30%. Equivalent to 1890-line/TV(1/4" CCD),2520-line/TV(1/3" CCD).**The picture becomes soft focus beyond 6X zoom telephoto position while wideangle lens is on the camera.