1)When taking photo under are strong light sources - such as the sun, you can get the familiar 'flare' spots on images. The flare will seriously degrade your images. Different lenses give different patterns of flare; The shapes of the larger spots depend on the shape of the lens iris, and the colours depend on the glass and coatings in use. A lens hood can stop light coming into the lens at extreme angles and being reflected inside the lens. This can lower the contrast of the image. Lens hoods also have two other very practical uses. They help to protect the lens when stood on a surface or in your camera bag and when changing lens, and also help to keep your fingers away from the front of the lens.