Sigma CPL-21 Water-Resistant Circular Polarizer Filter (52mm)

The Sigma CPL-21 Water-Resistant Circular Polarizer Filter (52mm) combines creative image control with everyday lens protection in a redesigned filter that complements the appearance and optical quality of Sigma lenses. Ideal for landscape, travel, architecture, and outdoor photography, the CPL-21 helps photographers achieve cleaner, more vibrant imagery directly in-camera.

The circular polarizing design helps reduce reflections and glare from non-metallic surfaces such as water and glass, making it easier to photograph through reflective surfaces or capture greater detail in outdoor scenes. By reducing unwanted reflected light and atmospheric haze, the filter can also increase contrast and color saturation, helping skies, foliage, and other natural elements appear richer and more defined.

Constructed from clear optical glass, the CPL-21 maintains high optical quality while also helping protect the lens's front element from dust, dirt, and scratches. A water-resistant optical coating repels liquids from the filter surface, providing additional protection when shooting outdoors or around moisture.

An improved surface treatment on the metal filter frame helps reduce internal reflections for cleaner image reproduction. Sigma's updated low-profile frame design also helps prevent unwanted vignetting, including when the filter is used with compatible ultrawide-angle lenses.

Combining 52mm compatibility, circular polarization, glare and reflection reduction, enhanced contrast and saturation, water resistance, and a low-profile frame, the Sigma CPL-21 Water-Resistant Circular Polarizer Filter provides both creative control and practical protection for photography in a wide range of environments.