Hoya Circular Polarizer Filter 49mm

Every Hoya filter is the result of research, expertise, and precise facilities, supported by comprehensive quality controls. Before production begins, the controls are first programmed into a computer. Then, the best materials are carefully mixed by an automatic V-mixer for absolute homogeneity. After melting with advanced equipment, this material is then precisely shaped using automatic direct pressing machines. The pressed blanks are then slowly and continuously cooled to relieve stresses, and are subsequently polished by high-speed double-sided polishing machines that ensure precise surface quality and perfect flatness.

The next step is the coating process, which enhances the light transmission of the filter. The transmission properties are checked with a spectrophotometer, after which an ultrasonic cleaner removes all foreign substances from the surfaces. Only after passing all quality inspections by Hoya are the filters assembled, finished, and prepared for shipping to customers around the world.