HARDENED 8 LAYER WATERPROOF MULTI-COATING THAT IS SCRATCH & STAIN RESISTANT Hoya HD (High Definition) Filters are Hoya's highest quality filter.
Newly developed industry leading 8-layer multi-coating yields an average light transmission rate of 99.35% between 400 and 700nm (visible spectrum). These coatings greatly reduce reflections off the surface of the glass allowing you to capture more light in your photos.
As with all HOYA multi-coatings,HD HMC is applied in a furnace at high heat, bonding the coating to the surface of the glass. This process is called "hard coating" and it is far more durable than other coating techniques. The chemistry of the top layer is formulated not just to be more durable but to be resistant to oil stains. This means that finger prints and other oils are much easier to remove.