The Sigma 105mm Ex-DG Circular Polarizer Filter helps to reduce reflections and glare by filtering out light that has become polarized due to reflection from a non-metallic surface. This results in a noticeable increase in the saturation of skies and foliage, as well as clearer imagery when photographing in hazy conditions.
A circular polarizer differs from a linear polarizer in that it contains a quarter wave plane in addition to the linear polarizing filter. The addition of this quarter wave plane is to circularly polarize the linearly polarized light for the use of autofocus and exposure functions. Due to how the light is broken down and filtered with a linear polarizer, autofocus and exposure accuracy become skewed during use. When the light becomes circularly polarized, it permits the use of these functions.
This filter has a wide filter mount to help reduce the likelihood of vignetting when working with wide-angle lenses. It is constructed from optical glass and features Sigma's super multi-layer coating to reduce flare and ghosting while helping to increase overall clarity and contrast.
Helps to reduce reflections and glare by filtering out light that has become polarized due to reflection from a non-metallic surface
Polarizing filters arrange, and filter, directionally polarized light perpendicularly to the reflected light, allowing for the absorption of much of the light
Clears up haze in distant landscapes and provides more saturated, vivid colours
Strongest effect when used at a 90° from the sun
Circular polarizers are ideal for use with digital cameras and autofocus lenses where a linear polarizer will often disrupt auto exposure and focus features
Wide filter mount minimizes vignetting when used on wide-angle lenses
Super multi-layer coating helps improve image clarity by reducing flare and ghosting