什么是紫外线过滤器，您需要它来保护相机镜头吗？

A UV filter is a glass filter that attaches to the front of your camera lens and blocks ultraviolet rays. They used to be necessary for film photography, but now most photographers use them to protect their lenses.

紫外线滤镜是一种玻璃滤镜，它附着在相机镜头的前部并阻挡紫外线。 过去它们是胶片摄影所必需的，但是现在大多数摄影师都使用它们来保护镜头。

There’s a lot of misinformation about UV filters out there. Some photographers swear they’re essential, while others are equally certain they’re a total waste of money. In some photography shops, the salespeople won’t let you leave with a new lens unless you’ve also ponied up for a UV filter; in others, they’ll laugh you out the door if you try to buy them. So what’s the truth? Let’s find out.

关于紫外线过滤器的信息很多。 一些摄影师发誓他们是必不可少的，而另一些摄影师同样确定他们是浪费金钱。 在某些摄影店中，除非您还准备使用紫外线滤镜，否则销售人员不会让您带上新镜头。 在另一些国家，如果您尝试购买它们，他们会在门外嘲笑您。 那么真相是什么？ 让我们找出答案。

紫外线过滤器有什么作用？ (What Does a UV Filter Do?)

A UV filter blocks UV light as it enters the lens. Think of it as sunscreen for your camera. Some old photography films were very sensitive to UV light so, if you didn’t use a UV filter, you would end up with a blue haze in your photos. This was especially common if you were shooting somewhere there was a lot of UV light, like on a really sunny day or at high altitude. You can see it in this polaroid by MoominSean on Flickr.

紫外线过滤器会在进入镜头时阻挡紫外线。 将其视为相机的防晒霜。 一些旧的摄影胶片对紫外线非常敏感，因此，如果不使用紫外线滤镜，最终照片中会出现蓝色雾状。 如果您在有很多紫外线的地方进行拍摄，例如在晴天或高海拔地区，这种情况尤其常见。 您可以在Flickr的MoominSean的这张宝丽来照片中看到它。

The thing is, modern films and digital sensors just aren’t sensitive to UV light. It doesn’t affect them the way it does older films. This means you don’t need a UV filter to block UV light in order to take good photos. However, this hasn’t stopped UV filters from picking up a secondary use as a protective filter for your lenses. Some camera shops are reluctant to let you walk out the door with a new lens, if you haven’t also bought a UV filter to protect it.

关键是，现代胶片和数字传感器对紫外线不敏感。 它不会像老电影那样影响他们。 这意味着您不需要紫外线过滤器即可阻挡紫外线以拍摄出优质的照片。 但是，这并没有阻止UV滤光片再次用作镜片的保护滤光片。 如果您还没有购买紫外线滤镜来保护它，则有些相机商店不愿让您带上新镜头进入大门。

紫外线过滤器会保护您的镜片吗？ (Does a UV Filter Protect Your Lens?)

The basic idea is that, if you drop your $2,000 lens, instead of breaking the front element of the lens, you break your $35 UV filter instead. It’s a lot easier to just pick up a new filter rather than ship your lens off to—possibly—get repaired. Unfortunately, while the idea sounds good in theory, it doesn’t really hold out in practice.

基本想法是，如果您丢下$ 2,000的镜片，而不是破坏镜片的前部元件，而是要破坏$ 35的紫外线滤光片 。 只需购买一个新的滤镜，而不是将镜头运到(可能是)进行维修，就容易得多。 不幸的是，尽管这个想法在理论上听起来不错，但实际上并没有得到支持。

Steve Perry from Backcountry Gallery drop tested a load of different lens filters and lenses and what he found was that the filters added minimal, if any, protection.

来自Backcountry Gallery的Steve Perry投下了不同镜头滤镜和镜头的负载测试，结果发现这些滤镜加了最少的保护(如果有的话)。

Perry’s big takeaway was that the glass in UV filters was a lot weaker than the glass used in the front element of lenses so the filters break from drops that don’t even ding a lens, regardless of whether or not there’s a filter on it. Also, if a lens was hit hard enough that the front element was damaged, there was normally large amounts of internal damage too. Even in the few cases where the UV filter might have protected the front element, the lens was dead anyway.

佩里的一大收获是，紫外线过滤器中的玻璃比镜片前部元件中使用的玻璃要弱得多，因此，无论是否装有过滤器，过滤器都会从甚至不使镜片掉落的水滴中掉落。 另外，如果用力撞击镜头以至于损坏前部元件，通常也会产生大量内部损坏。 即使在少数情况下，紫外线过滤器可能会保护前部元件，但镜头还是死了。

This all means that if you drop your lens with a UV filter and the filter breaks but not the lens, all you probably did was break a filter. The lens would have been fine either way. And if you drop your lens without a UV filter and it breaks, a filter wouldn’t have saved it.

这一切都意味着，如果您用紫外线滤镜掉下镜头，但滤镜破裂了，但镜头没有破损，您可能要做的就是弄破滤镜。 无论哪种方式，镜头都可以。 而且，如果您在没有UV滤镜的情况下掉落镜头而损坏，则滤镜将无法保存。

This doesn’t mean UV filters offer no protection. It just means they don’t offer any protection from hard drops. They’re great for protecting your lens from dust, scratches, sand, sea spray, and other small environmental hazards.

这并不意味着紫外线过滤器不提供保护。 这只是意味着他们没有提供任何保护以防硬摔。 它们非常适合保护您的镜头免受灰尘，划痕，沙土，海浪和其他小环境危害。

紫外线滤光片的光学效果 (The Optical Effects of UV Filters)

There’s one final thing to consider about UV filters: putting any extra glass in front of your lenses affects the image quality.

关于紫外线过滤器，还有最后一件事需要考虑：将多余的玻璃杯放在镜片前会影响图像质量。

UV filters block a small percentage (between 0.1 and 5%) of the light that passes through them. Because of how the light interacts with your filter, this reduces the sharpness and contrast of your images very slightly. It’s a barely noticeable effect and easily fixed in Photoshop, but it is there. It’s also worse in cheap filters from no-name brands. Filters from the likes of Hoya, B+W, Zeiss, Canon, and Nikon showed the least impact, while filters from brands like Tiffen showed the biggest.

UV滤镜会阻挡一小部分(0.1到5％之间)通过它们的光。 由于光线与滤镜之间的相互作用，因此会非常轻微地降低图像的清晰度和对比度。 这几乎没有什么明显的效果，可以在Photoshop中轻松修复，但是就在那里。 在没有名牌的廉价过滤器中，情况也更糟。 来自Hoya，B + W，Zeiss，佳能和尼康等公司的滤镜影响最小 ，而来自Tiffen等品牌的滤镜影响最大。

More seriously, UV filters also make it more likely that you’ll get lens flare or ghosting in your images if you’re shooting a scene with a bright light source in it. In the image above, you can see some artifacts caused by the UV filter and the lens flare.

更严重的是，如果在使用明亮光源拍摄的场景中，UV滤镜还可能使图像中出现镜头光晕或重影。 在上图中，您可以看到由UV滤镜和镜头光晕引起的一些伪影。

您应该使用紫外线过滤器吗？ (Should You Use a UV Filter?)

Deciding whether or not you should use a UV filter isn’t a simple question. It really depends. The best advice I can give you is:

确定是否应使用紫外线过滤器不是一个简单的问题。 真的要看 我能给您的最佳建议是：

• A UV filter won’t protect your lens from much more than dust and scratches. If you’re shooting at the beach or in the desert, putting one on is a good idea, but otherwise, you’re probably fine without one.
  紫外线过滤器不会保护您的镜头不受灰尘和划痕的影响。 如果您是在海滩或沙漠中拍摄，穿上一个是个好主意，但是否则，没有一个可能就没事了。
• UV filters have a small effect on the quality of your images. Most of the time, it won’t make a difference. But if you absolutely need the highest quality image possible, or your photos are showing lens flare and other artifacts, you should remove your UV filter.
  紫外线滤光片对图像质量的影响很小。 在大多数情况下，它不会有所作为。 但是，如果您绝对需要最高质量的图像，或者您的照片显示出镜头光斑和其他伪影，则应卸下紫外线过滤器。

I’d argue that there’s definitely a place in your camera bag for a UV filter. But it’s up to you whether keeping it on your camera all the time is worth it. I prefer to take my UV filters off if they’re affecting my images, other people prefer to put them on if they’re shooting somewhere dirty.

我认为您的相机包中肯定有一个用于放置紫外线滤镜的地方。 但是，是否值得一直将其始终留在相机上取决于您。 如果它们会影响我的图像，我更喜欢取下紫外线过滤器，如果别人在肮脏的地方拍摄，我更喜欢戴上它们。

Image Credit: Abraksis/Shutterstock

图片来源： Abraksis / Shutterstock

翻译自: https://www.howtogeek.com/355998/what-is-a-uv-filter-and-do-you-need-it-to-protect-your-camera-lens/