Lens flare spoils many pictures. Even when it does not show as a streak across the image, it can cause overall loss of contrast. Flare is caused by light from bright sources - such as the sun or spotlights - hitting the front element of the lens at an angle. This sets off a series of unwanted internal reflections and refractions. This genuine Canon lens hood EW-73D protects the front of the lens from this side lighting.
Lens hoods are shaped specifically for the type of lens. Some are straight, some are petal-shaped. They can also be reversed on the lens for storage.
This lens hood fits the following Canon lens:
EF-S 18-135mm f3.5-5.6 IS USM