Aside from making the lens look longer and bigger and thus more impressive to non-photographers, lens hoods (sometimes called shades) serve two basic functions. First, they help reduce the amount of stray light hitting the surface of the lens. This is a good thing, since non-image-forming light coming into the lens at an angle results in lens flare. Lens flare can result in lower-contrast images or, in extreme cases like light from the sun, can result in big glowing blobs in the final photo. Second, lens hoods serve as physical protection for the lens - the plastic or metal tube can absorb blows that might otherwise hit the glass itself.
Lens hoods come in a number of basic forms. The two types sold by Canon today are tube-shaped hoods and petal-shaped (notched) hoods, made of hard black plastic. The petal-shaped type are sometimes called “perfect” lens hoods and shield the lens more effectively than simple tubes of the same weight. This is because the notches are cut out to match the rectangular shape of the imaging area (think about it).
Some hoods clip onto the lens, some twist on bayonet-style and some screw onto the end. Some are lined with black light-absorbing flocking and some are not. You can also buy flexible adjustable rubber hoods from third party makers, but Canon do not sell any such hoods themselves.
Unfortunately, lens hoods are hugely overpriced. Camera makers somehow feel justified in charging massive sums for simple moulded plastic tubes. Ah well.
Wah... very professional and details. Previously, I planned to buy the lens hood too. However, when I know that it cost about $200-300. Wah!!! too expensive for such a small "black plastic" So I drop off the idea.
Does anyone think that taking photos with the hood would have much different for without this?
發表於 
發表於 
返回列表
