One of the most popular special-effect filters, the circular polarizer helps outdoor photographers - professionals and aspiring enthusiasts alike - capture that awe-inspiring image. Unlike a static single film polarizer, the circular polarizer gives you control over the angle of the polarizing effect in relation to the light. By reflecting certain light rays, the polarizing filter only allows select light rays to enter the camera lens. From vibrant sunsets over the ocean to vast mountains and grand canyons to family photos in the backyard, the AmazonBasics circular polarizer will help take your outdoor images from simple to sublime. Circular polarizer--one of the most popular special-effect filters Deepens the intensity of blue skies; reduces or eliminates glare Multi-coating reduces reflection Ideal for outdoor photography; for use with auto-focus and non-auto-focus cameras Measures 55mm in diameter.