A lens hood is an accessory used in photography that attaches to the front of a camera lens. Its primary purpose is to block stray light from entering the lens, which can cause unwanted glare and lens flare. By reducing these effects, a lens hood helps improve the overall contrast and color saturation of images. Additionally, a lens hood provides physical protection for the lens, shielding it from accidental bumps, scratches, and dust. They come in various shapes and sizes, often designed to match specific lenses, such as those used with DSLR cameras or mirrorless cameras.