Why uv filter for lens

In this article, I will attempt to explain my own point of view and discuss the main arguments for and against using UV filters.

Most of these arguments apply equally to clear protective filters. I assume that the UV filter being used is of similar optical quality to the lens elements themselves. This is generally true for the best multi-coated filters from good manufacturers, but may not be true for the cheaper filters.

This argument is almost completely spurious for modern digital cameras. With old film cameras it was often necessary to use a UV filter because film is extremely sensitive to UV light. However, digital sensors are generally rather insensitive to UV, so the problem doesn't arise to anything like the same extent.

Having said that, I have seen some evidence that for certain lenses a UV filter can reduce the purple fringing caused by longitudinal chromatic aberration. The purple fringing of longitudinal chromatic aberration only occurs in particular circumstances and is not to be confused with the much more common coloured fringing caused by lateral chromatic aberration most noticeable in the corners of the frame.

My personal view is that these effects are almost always insignificant and do not provide a good enough reason for using UV filters on a regular basis with digital cameras. I have seen no good evidence that the presence of a filter significantly reduces the chances of seriously damaging the lens. Secondly, protection against dust, dirt, smears and scratches on the front element of the lens - The presence of a filter on the lens certainly protects the front element, as the dust, dirt, smears and scratches get on the filter instead.

Which is preferable? The filter is flat and easily removed, which makes it much easier to clean. Also, if it does get scratched, or gets so dirty that it is too difficult to clean thoroughly, then it typically costs much less to replace than the lens. On the other hand, many photographers argue that lenses do not need cleaning very often and the chances of scratching the lens are very low, so it is better to save your money and go without the filter.

This is true in theory except possibly in those rare cases of lenses that have been specially designed for use with a filter. However, the loss of image quality is likely to be very small in practice and so the real question becomes: Is the loss of image quality significant to me?

In trying to answer this, there are several different aspects of image quality that need to be considered:. I use the term flare to mean an overall veiling of the image or parts of the image due to stray light, while ghost images are secondary images of very bright light sources, usually badly out of focus and sometimes showing extreme coma, astigmatism and chromatic aberration as well.

Both flare and ghost images are caused by unwanted reflections or scattering from the various exposed surfaces within the lens and camera body. The glass surfaces of all the lens elements will contribute, as will the glass surfaces of the filter. Typical modern lenses contain up to 15 or more elements, and the addition of one more element the filter is not likely to make much difference in most practical circumstances.

I have never seen any convincing evidence that the presence of a good quality filter increases flare to any noticeable extent with ordinary camera lenses. However, there is a particular circumstance in which the presence of a filter may cause noticeable ghost images. With some lenses, when used at full aperture or nearly so , light reflected from the sensor back through the lens may be reflected from the rear surface of the filter back into the camera producing a ghost image on the opposite side of the optical axis.

Ghost images of very bright lights are often visible in night shots taken with a very fast lens at full aperture if a filter any filter, the type is irrelevant is being used. Although much fainter than the primary images, they can be very noticeable as they will be in focus if the lens is focussed at infinity and the lights causing them are in focus. These ghost images will disappear if the filter is removed, or if the aperture is reduced sufficiently i.

With a UV filter on the lens. The greenish spots of light in the central portion of the frame are ghost images of some of the very bright floodlights. It is only a circular area around the centre of the image that is subject to these ghost images. The diameter of this area reduces as the F-number is increased. Both the above images are overexposed and this makes the ghost images more noticeable. Even so, it is only the brightest lights that produce ghost images that are bright enough to be seen and then only when they occur against a relatively dark background.

In daytime images, it is extremely rare for ghost images to be noticeable unless the sun is visible in the frame and the air is clear so the sun shines brightly. Notice that there is considerable flare near the floodlights and this is the same in the two images.

The leftmost floodlight produces particularly strong flare which can be seen both as a fuzziness and spreading of the floodlight itself and also as a purplish haze which seems to surround the crane on the extreme left.

I have never seen any convincing evidence that a good quality UV filter causes noticeable loss of light through the lens. Indeed, that would not be expected as the filter is just one additional glass element and most modern lenses already have at least 7 elements and often twice that number or even more. Again, I have never seen any evidence that this is significant for a good quality filter on normal camera lenses.

Good quality filters should have optically flat surfaces that do not disturb the direction of the light rays passing through the filter. If there is any slight variation from optical flatness as may occur with a very cheap filter , the effect will be most noticeable with extreme telephoto lenses because of their magnifying effect. My evaluation of the evidence is that there is no really compelling evidence either to use a filter or not, except in a very few situations when it is better not to use a filter to avoid in-focus ghost images.

Personally, I do have UV filters on all my lenses and only remove them in those very rare situations for which I know they may cause ghost images. My main reason for using filters is that I like to keep my lenses very clean and I feel more confident in cleaning the filter than in cleaning the surface of the lens. However, I think those photographers who choose not to use filters have a sound case as well! In comparing images taken with and without a filter, one thing I have noticed in doing the tests is that even a slightly dusty lens occasionally has a noticeably deleterious effect on the image.

This only occurs in extreme lighting conditions such as when the sun is shining brightly and is within the image frame, or very close to it. Under such circumstances, light scattered by dust particles on the front element of the lens or on the filter can significantly increase the stray light falling on the image. It's generally not worth worrying about a little dust on the lens or filter. In normal circumstances dust on the front element has no visible effect at all.

But, if you are shooting into a bright sun or other very bright lights, then it is a good idea to clean your lens and filter first. The shop sold me a UV filter, one for each lens kit-lens and the superzoom. I put them on my lenses and never gave it another thought. Pictures with the zoomlens often came out unsharp and with poor colour - not all of them with poor colour, but a considerable number. I always atributed that to the lens being cheap.

Until a week ago after looking over another batch of pictures I started to think, what about that UV filter So last weekend I took some photos under more-or-less controlled circumstances, outdoors with good sunlight, with and without UV filter. The kitlens didn't show the same problem - the UV filter did make pictures less sharp but never noticed the colour being so much off. My conclusion therefore is that a UV filter can definitely be harmful, but you need to evaluate the combination of filter and lens.

I just sold a vintage Leica lens. It was in otherwise nearly mint condition except some well meaning previous owner seriously damaged the front element by cleaning it, greatly reducing its value.

Without doubt, today's coatings are much more durable than the ones used in those old lenses, but they can still be easily damaged. I agree with the author, leave the filter in place unless there is a reason to remove it.

I'm in the camp of better safe than sorry. I mainly work photographing children in schools and at events and anything can happen around children. I've definitely had a couple instances where an accidental drop or hit with an errant ball thrown by a year-old has broken the filter and not damaged the lens at all. FWIW, I somehow got a drop of coffee on a lens several years ago.

I noticed it in the field and did not have decent cleaning cloths with me and it did not seem to affect the image so I left for later cleaning. I cleaned it that night and the coffee eroded a surface coating and the erosion was plainly visible by the human eye, but did not seem to affect image quality. It did, however, affect re-sale value.

From that day on, I put protective filters on my camera on the day I receive them. I don't use any UV filter on any of my lenses, I just keep the lens hood on, and when the lens hood is not used I make sure not to drop the camera or bang the lens against anything. Speaking of "scratching the lens"; It is first of all unlikely indeed, since glass is hard and you'll need to get a hard material onto the glass with some significant force.

If you have some light scratches scattered all over, it's unlikely to show up. When you have some ridiculous amount of wear right in the center, then it will probably ruin the image. Just go and look up any video where they actually intentionally damage a lens and then demonstrate the "difference" of which there usually is none. And I stand behind the principle of "better safe than sorry" and some slight chance of "lower image quality" unless it's just horrible glare or something like that isn't going to overrun that principle.

On two occasions I found my filters badly cracked or shattered but the lenses they protected remained undamaged and allowed me to continue with my photographic assignments. We forget to include in our calculations the time and the loss of heart when you've lost the use of a lens you were counting on. As the commercial says, don't leave home without it. How can you assume the lens would have been broken if it weren't for the UV filter?

Two things: the UV filter sits much further forward of the front element so is significantly more exposed and at risk. Secondly, the front element if a lens is significantly tougher and more scratch resistant than any filter. UV filters are fragile; it's hardly any surprise they break so often. The degradation due to the UV filter only occurs under very rare conditions. NOT using it causes instead serious issues! Except for the small pocket-camera lenses, the lenses of any camera even when getting continuously covered-uncovered get exposed to dirt, fingerprints and other types of smears: they even get scratches!

To avoid degradation of pictures and long-term degradation of the lens, they require frequent and difficult cleaning, and there is no remedy when there is a scratch! It is much better to keep the lens at factory quality by having a permanent UV filter which can be easily cleaned and also inexpensively replaced if it gets scratched. What about the photographer's own eye used for composition and for focus? Won't the lens elements of the camera damage your eye, and create possible increase in the amount UV damage exposure to the eye.

In the old days shooting with film, most of the time I wouldn't shoot more than a couple rolls of film. Today's world, it's not unusual to go out and shoot pictures. I leave the lens hood on all the time. Protects the element. I have had good luck with microfiber clothes, a dust blower, and just fogging the front element with my breath and wiping it clean. So far, I have not noticed an issue, and let's face it, thats how we clean our polycarbonate eyeglasses, and they don't end up getting scratched.

The shrapnel from a broken filter can damage the front element anyway. So far so good :. I don't understand the logic supporting comments that after a drop the filter was broken and therefore if the filter hadn't been screwed on the lens would have broken. Maybe the filter just can't take as much shock as the lens and its breaking had nothing to do with protecting or not protecting the lens. This link is from some actual testing that was done and the conclusion was "the UV filter broke simply because they're more prone to breakage than the lens itself is.

I've always had a UV Filter on all of my Cameras. I took a trip to NY with a new camera I had not purchased a filter for. Bad mistake. I went to the top of The Empire State Bld. If I had a filter on I would have been cleaning often like I do out of habit. So I took spotty pictures the rest of the night, because I was scared to clean my Lens.

So now on I will have a filter and when it gets messy from cleaning it, I will trash it and put on a new one. To make sure I don't get any dark areas or the loss of overall contrast, I will use an upsize kit so the filter is larger than the end of the Camera lens. Your mistake was being too scared to clean your lens! Lens front elements are extremely tough.

Vastly more resilient to scratches than fragile UV filters. I was reading earlier today that some of the lenses with drop in filters require a filter in place as part of the optical system. That is true. A very few lenses are designed to be used with a filter in the optical path and for these lenses the image quality may be slightly reduced if the filter is omitted.

Two points, first; even if you ignore the secondary reflections, the haze around the lights and the loss of overall contrast in the second image above seems much worse with the filter. Am I the only one seeing this? Second; I think it should be considered that the filter glass is much thinner and much more exposed than your front lens element, hence much, much easier broken.

I feel this needs to be pointed out as many times a filter will be broken or damaged when the lens would have remained untouched. With that being said, I do feel there are times when a filter offers inexpensive protection for your lens for example if there is dirt, sand, or liquid flying around. I see the 2 shots are framed differently This could throw the comparison off. No, you are not the only one that noticed the lessor quality of the second image.

I made a quick judgement that the two images were inadvertently, switched. I say this because I have read several online articles, supposedly by experts, supporting the use of UV filters, when it comes to decreasing haze in scenic landscape photography, especially under mid-day sun. The comparison images in these article suggest that the filters decrease haze, thereby increasing saturation and clarity in bright sunlight.

Mine arrived today: I guess I will have to make my own decision. The comparison images suggest that the filters decrease haze, thereby increasing saturation and clarity in bright sunlight. Very informative post. I too have used filters nearly permanently for years just because I'm happier cleaning an affordable filter than a the front element of an expensive lens.

I've never yet seen the ghosting, but I'll be on the lookout after reading this. However, I take issue with one point. Both were broken behind the lens cap after "mishaps". In both cases I unscrewed the filter wreckage in trepidation but was delighted to find absolutely no damage to the lenses!

A quick puff of air to blow away the fragments of glass, and straight away ordered replacement filters For me this is strong evidence that a filter can indeed protect a lens, especially when the hoods are off or reversed, and the lens caps are on. I'm surprised you found this to be strong evidence. Broken behind the lens cap? The front element of the lens, of course, sits much further back. Also, it highlights how fragile UV filters are. Smart TVs Ads.

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Reader Favorites Take Screenshot on Windows. Mount an ISO image in Windows. Boot Into Safe Mode. Disable Startup Programs in Windows. Where to Download Windows Legally. It would be a shame if your photos are spoiled because of the UV filter, so make sure to always choose a good-quality one. If you're taking photos with back light or glares, the filter can cause extra lens flare.

Make sure to take it off your lens before taking photos in these kind of situations. Ordered before , delivered tomorrow for free Free exchange Most customer-friendly webshop Business Stores Customer Service. Written by Sanne 18 March What does a UV filter do and how do you use it? If you read something about lens filters, you probably see the term UV filter pop up often. But what do you need a UV filter for? What are the biggest advantages of this filter?

I'll answer those questions in this article.