The Kenko 58mm Zeta EX Circular Polarizer Filter is only 0.8mm Thin Glass, 10g Feather Light Filter that uses a specially polished 4 layer thin glass and ultra thin frame combination making it wide-angle lens compatible. Even with being this thin, the Zeta EX still has the front screw on function for attaching a lens cap. The super light weight mechanically benefits certain AF lenses. Zeta EX transmits as much as 25 percent more light through the polarizing film, giving the photographer about 1 stop lighter than a standard circular polarizer. This innovative coating will not interfere with any color or light transmission. Reflections are eliminated by allowing light to enter the filter at virtually any angle. Nano Glass Technology creates an ultra smooth surface from the finest particles of glass, making it stain and scratch resistant without any effect to the image.