Main Features:

1)Massa Circular Polarizer takes advantage of Hoya's patented optical glass technology to create a hardened glass that is thinner than the normal optical glass. This allows the overall thickness of the filter to be reduced to avoid vignetting when used with ultra-wide angle lenses.
 
 
The main function of the Circular Polarizer filter (CPL Filter) is eliminating the scattered light in the air,as well as the reflected light from the non-metallic surfaces like water and glasses.It also serves as a multi-coated lens protector to prevent dust and scratches.

It allows the parallel light to go through the lens only,so that the camera can enable colors to become more saturated and appear clearer with better contrast between the clouds and the sky because it can be used to darken bright skies .Atmospheric haze and reflected sunlight are also reduced,and in color photographs overall color saturation is increased.

When you rotate the CPL filter in its mount, the effects will show up immediately. The filter factor varies according to how the filter is rotated and its orientation to the sun.

Unintended vignetting is the most common defect when operating  with super-wide-angle lens.  To entirely eliminate this problem, you need a high quality filter with excellent multi-layer coating and extra-thin frame. That is why Massa stands out from its peer.