lens hood

 In photography, a lens hood or lens shade is a device used on the end of a lens to block the sun or other light source in order to prevent glare and lens flare.The geometry of the lens hood can vary from a plain cylindrical or conical section (much like a lamp shade) to a more complex shape, sometimes called a petal, tulip, or flower hood. These more complex shapes of lens hood take into account the final image's shape and aspect ratio.[3] This allows the lens hood to block stray light with the higher portions of the lens hood, while allowing more light into the corners of the image through the lowered portions of the hood, thereby reducing the amount of vignetting in the final image.Ideally, lens hoods should increase in length, and therefore in efficiency, as the focal length of the lens increases and the angle of view reduces. Lens hoods are more prominent in long focus lenses because they have a smaller viewing angle than that of wide-angle lenses. For wide angle lenses, the length of the hood (away from the end of the lens) cannot be as long as those for telephoto lenses, as a longer hood would enter the wider field of view of the lens.VY Optics could manufacture varied size of lens hood or lens shade,picture shown is 37mm.OEM is available,too.All lens hoods are fit for Canon,Nikon,Olympus,JVC,Kadak,Fuji,Casio and so on.