
The main purpose of a polarizing filter is to remove reflections from, for example, water, glass, and other non-metallic surfaces. A polarizing filter also deepens the color tones of an image, e.g. green is greener and the blueness of the sky is increased, making clouds appear whiter than usual.
A circular polarizing filter consists of two overlapping pieces of glass, the front of which can be rotated infinitely as needed. The effect is strongest when the sunlight is at a 90-degree angle to the subject, and the polarization is set to its strongest.
The edge thickness is only about 5mm, meaning there is no risk of vignetting. The end of the filter has a female thread that corresponds to the mounting thread, which the normal lens cap of the lens attaches to.
The Hoya Fusion (also known as the EVO series) is an improved version of the Hoya Pro1 filter. The filter has an anti-static coating that prevents dirt from sticking to the filter. If you manage to get something on the surface of the filter, it can be easily removed by lightly wiping it with a microfiber cloth. The surface is also scratch-resistant.