Lens Hood Function

At first I did not understand the lens hood function, I think just for the variation in front of the lens. After I was looking for from several sources I finally understand usability lens hood.

Briefly lens hood is a tool used at the end of the lens to block the sun or other light sources to prevent glare and lens flare. Another function is
1. Google glare blocking.
2. Protect the glass lens or filter.
3. Make your camera look cool.

Geometry of the lens hood can vary from a cylindrical or conical part plain (such as light colors) to more complex cut sometimes called a tulip, flower petals or hood (as seen in some photos), which results in a reasonable good shade without blocking the field of view lens and thereby produce vignetting. True petal shaped lens hood shade to produce more than normal lens hood with the same final diameter. Square lens hood might be better.

Lens hoods are more prominent in the focus of a long lens because field of view at an angle of view smaller than a wide-angle lens. For wide angle lens, the length of the hood (away from the tip of the lens) can not all like to telephoto lenses due to the point of view.

Lens hoods are often designed to fit on the lens that fits both facing forward, for normal use, or backward, so that may be stored with the lens hood without occupying a lot of extra space. Some flexible lens hood and collapse for storage.

In addition, they offer some physical protection for the lens because the hood extend further than the lens itself.