EW-83C II Lens Hood compatible with Canon EF 17-35mm f/2.8L USM Lens hoods are primarily designed to prevent unwanted stray light from entering the lens by extending and shading the end of the lens. The non-glare matte finish on the inside further prevents or limits lens flare. No vignetting will show with the hood on. With the extended lens end, you will also benefit from extra protection from accidental impact. Reduce halo and enhance photo color and saturation. Reduce black angle situation. Prevent the entry of non-imaging light. The design makes it firmly on the lens.