Spe Tulip 58Mm Flower Lens Hood (Black) For Canon Eos 55-250Mm 18-55Mm Ef Lens The lens hood is a piece of plastic that clips onto the front of a camera lens and extends beyond it. Lens hoods serve two primary purposes: (1) reducing lens flare, and (2) protecting the lens from damage. The intended purpose of the lens hood is simply to reduce lens flare, but the protection it provides to the glass elements of the lens is a beneficial side-effect.