After a unique collaboration between Hoya and esteemed wildlife photographer and conservationist B. Moose Peterson of Wildlife Research Photography, the 52mm Warm Circular Polarizer Glass Filter was born. This high-quality filter ingeniously combines the functionality of a polarizer with the warming effects of an 81A filter. For decades, photographers have relied on polarizers to eliminate reflections from non-metallic surfaces such as water and glass. They are also instrumental in darkening blue skies to enhance contrast in landscape photography. However, using traditional linear polarizers with today's auto-focus cameras, which often employ a split beam metering system, can lead to exposure errors due to their light absorption properties. This is where our durable and effective circular polarizer filter comes into play. It delivers the same optical effect as a linear polarizer, but without causing exposure issues with modern metering systems. A common side effect of both linear and circular polarizers is that they tend to ""cool down"" the overall color balance of a scene, often resulting in a slightly bluish tint. Our versatile 52mm Warm Circular Polarizer Glass Filter addresses this issue with the addition of 81A glass. This corrects the color temperature, restoring the scene to the original 5500K color balance ideal for daylight film. The 81A glass not only creates a more pleasing and warm color balance for the entire scene, but the circular polarizer also increases color contrast and reduces the effect of atmospheric haze. Easy to use and highly effective, this filter is a must-have tool for photographers looking to capture stunning, high-contrast images in a variety of lighting conditions..