Hoya 37mm slim circular polariser filter allows you to decrease unwanted reflections and glare from non metallic surfaces such as water glass etc for maximum effect a camera angle of 30 degrees from the reflecting surface is ideal it also enables better contrast by allowing colours to become more saturated and appear clearer this effect is often used to increase the contrast and saturation in blue skies and white clouds the thin frame of the hoya slim circular polariserrsquos reduc