A metal, hard plastic, soft and other texture, has the following effects:
 
1. In the backlight, side light or flash photography, to prevent the non-imaging light to enter, to avoid haze.
2. In the light and side light photography, you can avoid the surrounding scattered light into the lens.
3. In the light photography or night photography, you can avoid the surrounding interference light into the lens.
4. To prevent accidental damage to the lens, but also to avoid finger contact with the lens surface, but also to some extent for the lens to cover the sand, rain and snow.

 
Hoods are available in a variety of sizes and should be chosen to match the focal length of the lens. The shorter the lens focal length, the larger the viewing angle, the shorter the hood. Such as the cover of the standard lens hood used in wide-angle lens, the screen will inevitably produce the consequences of imaging can not be around. On the contrary, it can not play the role of shading. When using a zoom lens, it is best to use a self-supporting telescoping hood.
 
Hood is widely used in backlight photography, in general, to avoid glare. However, glare may still occur if the light source is at a short distance. At this point, you can manually block the light shield on the light source side. Whether to eliminate the glare, to observe clearly from the viewfinder.