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Are there any real downsides to using a UV filter?

I know that a poor quality UV filter can effect image quality ... but, assuming I use a good quality UV filter, will that actually be an issue? Is there any other reason not to use one?

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    \$\begingroup\$ As an objective counterpoint to many of the assertions below--bolstering some of them, casting doubt on others--check out the lenstip review on UV filters. Filters were rated on transmission, flare, and vignetting. Some of the photos of the highest-rated filters actually seem to improve color saturation and contrast slightly. The lowest rated-ones did not perform even as well as an old piece of window glass! \$\endgroup\$
    – whuber
    Apr 14, 2011 at 4:28
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    \$\begingroup\$ @whuber: (1) site has been already mentioned below (2) can't find your conclusion of improving saturation nowhere stated in article (3) content: cutoff frequency of silicon nitride-coating of CMOS nowhere mentioned (4) content: dubious claims of susceptibility of coating to soap. \$\endgroup\$
    – Leonidas
    Apr 18, 2011 at 1:28
  • \$\begingroup\$ @Leonidas I am glad you consulted that review. Yes, it has its limitations. I hope that you and others might be inspired by this to identify and report on other reasonably objective sources of information bearing on the question, so that we can accumulate--and criticize--a body of knowledge rather than amassing a collection of largely unsupported (and somewhat conflicting) opinions. I am not criticizing the opinions that have been expressed, but only expressing a desire that they be backed up with facts. \$\endgroup\$
    – whuber
    Apr 18, 2011 at 15:23
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    \$\begingroup\$ See meta.photo.stackexchange.com/questions/981. I'd love to see some objective, analytical information here, since this is such a contentious topic. The lenstip article is a start, but is not without flaws. (Bounty added to the question for that purpose). \$\endgroup\$
    – mattdm
    May 2, 2011 at 18:38

11 Answers 11

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Yes.

  • It degrades image quality - adding more elements to a lens always reduces image quality; better filters will just do so less. One specific thing that happens is light reflecting between the front element of the lens and the filter, which can be reduced (but not eliminated) with coatings on the filter.
  • It makes it more difficult to use other filters. Either you have to remove it before adding the other filter, or you have to stack, which can introduce vignetting.

Whether the IQ reduction is noticeable and/or whether this is a good tradeoff is another question. :)

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    \$\begingroup\$ Good UV filter comparison can be found here: lenstip.com/113.1-article-UV_filters_test.html. \$\endgroup\$
    – Karel
    Jul 22, 2010 at 3:23
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    \$\begingroup\$ +1 - Reflection is an even bigger problem at night, with the high-contrast lighting. \$\endgroup\$
    – ex-ms
    Jul 25, 2010 at 1:56
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    \$\begingroup\$ So does it reduce image quality if I take a step backwards and introduce another 2 feet of air between the camera and the subject? Just because something in theory might make a difference doesn't mean it will in practice. \$\endgroup\$
    – Hank
    May 2, 2011 at 21:37
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    \$\begingroup\$ Another two feet of air doesn't introduce two more surfaces where the index of refraction changes, so you won't get any reflections from that air. Filters do, so it's a bit more than a theoretical difference. \$\endgroup\$
    – Evan Krall
    May 3, 2011 at 2:33
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    \$\begingroup\$ "adding more elements to a lens always reduces image quality" – Then why do you not use a zero-element lens for the ultimate in image quality? \$\endgroup\$
    – xiota
    Feb 13, 2019 at 1:09
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Cost of the filter is a very real downside. In case of a consumer-grade lens and a good UV filter, you might find yourself spending something around 1/5 of full replacement cost on "insurance" against dust (hardly affects image quality, removable), dropping and scratches (worse, but happen seldom).

If you use the lens in good conditions and/or rarely, you have certainly paid more than the risk is actually worth, while you could have used the money towards some other piece of equipment that would actually broaden your photographic abilities (e.g. a polarizing filter).

A lens hood would give you most of the same "insurance coverage" plus better optical quality for less cash. It makes access for possible scratchers and stainers harder; and in case of a fall, I would expect a hood to absorb the shock even better than a filter. And instead of degrading image quality with extra glass, it will enhance it by keeping stray light away.

In some environments with air pollution (sparks, paint, chemicals, oil, sandstorm, salty water, smoke), lens hood does not provide enough protection and using a protective filter does make sense.

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    \$\begingroup\$ +1 I don't use a filter on my $100 50mm f/1.8 because a good one would cost a very substantial proportion of the purchase price! \$\endgroup\$
    – fmark
    May 3, 2011 at 10:34
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    \$\begingroup\$ Some of my lenses, purchased second-hand, were actually cheaper than a decent UV filter for them would be :) \$\endgroup\$
    – Imre
    May 3, 2011 at 20:37
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    \$\begingroup\$ But would you put a protection filter on, say, a new 70-200 f/2.8 that set you back $2400 USD? I'm not trolling, I'm trying to establish a reference point. If cost is the reason for not applying a 'protection filter', then where does the cost become a tipping point, either way? \$\endgroup\$ Aug 16, 2012 at 22:45
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    \$\begingroup\$ Such lenses usually have big hoods and are often bought over cheaper alternatives because of the advantages of image quality. Many fast super-telephoto lenses don't even take front filters. Another expensive category that often doesn't take filters is ultra-wide lenses. I do sometimes use a polarizer on my most expensive lens (an f/4 tele zoom), but not because of protection. \$\endgroup\$
    – Imre
    Aug 17, 2012 at 8:24
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When the lens are designed they usually try to minimize the number of optical elements as each extra element will affect the image. Good filters make no noticeable changes, however it's still an extra element which can, for example, add a reflection in some rare cases.

Also, if you are using a wide angle lens, then choose low profile filter, otherwise you may get a vignetting.

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The use of any filter will result in the reduction of image quality. The extra air-glass interface that a filter introduces, no matter its quality, will degrade image quality. However, a high-end filter, such as one made by B+W or Heliopan, will keep this degradation to a level that is not perceptible under normal shooting conditions. Furthermore, if a clear or UV filter is attached to the lens, you'll need to remove it to use a polarizer, ND, or other filter, which can be inconvenient.

Light bouncing around between the filter and front element (or any other two air-glass interfaces) can degrade image quality by causing flare and reducing contrast. High-quality filters minimize this degradation by using anti-reflective coatings that reduce the amount of light reflected by the glass and increase light transmission. Low-quality filters have poor or no AR coatings and therefore can visibly degrade image quality.

I personally do keep clear (not UV) filters on my lenses (mostly B+W), so that I don't need to clean the front element of the lens directly, which can wear down the coatings on the lens--I'd rather replace a filter than replace the whole lens. You'll need to decide whether this protection and cleaning advantage outweighs the aforementioned loss of image quality and inconvenience. To me, it does, but you need to decide for yourself.

Another commonly cited reason for using a filter is that it can reduce the chance of the front element becoming scratched or broken altogether due to impact. However, a lens hood is generally more effective at providing this kind of protection, and this isn't the reason I keep clear filters on my lenses.

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Others have already discussed most pros and cons, but I'll just have to add this one thing: Some lenses don't like any filters, no matter how good or expensive.

For example, Canon EF 85/1.8 USM with an UV filter will create tinted reflections all over the picture from bright lights. This especially bad when shot wide open. I've tried and experienced this with two of these lenses and with high-end coated filters from B+W and Hoya. Ultimately I just gave up and never use any filters with this lens.

I guess this probably happens because the front elements of the lens throw some kind of reflection out of the lens in an angle small enough that any additional glass surface will reflect it back in.

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Another downside is that filters tend to add artifacts and reflections to an image due to the different sensitivity to light (than film). As a result, if you have a filter on, even a high end one, you can get weird artifacts. I have only found this to happen when taking night shots of bright lights, and then it is unmistakeable.

Here is an example of a forgettable image I took, but one that shows the artifacts being produced by the large porch lights on the house.

The nice thing about a filter is that its removable, nothing is permanent. I leave B+W UV filters on all my lenses, as it protects them and also keeps greasy fingers from the elements. When taking night shots or critical shots that don't need the filter, I take it off. Its easy to do.

edit: found another that's even more apparent.

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  • \$\begingroup\$ Can you show a with/without filter comparison? \$\endgroup\$
    – fmark
    May 9, 2011 at 12:07
  • \$\begingroup\$ So basically you are using filters as lens caps? \$\endgroup\$
    – Michael C
    Dec 25, 2014 at 18:32
  • \$\begingroup\$ @MichaelClark sort of, I guess. Only these lens caps are see-thru ;)...I prefer to clean the filter rather than the lens element, especially if the lens is coated (cleans easier). Plus, filter are cheaper to fix than lens elements when sharp or solid objects contact them. \$\endgroup\$
    – cmason
    Dec 29, 2014 at 16:16
  • \$\begingroup\$ So cleaning both sides of a multi coated filter is somehow less difficult and less risky to the coatings than cleaning one side of a lens' front element? \$\endgroup\$
    – Michael C
    Dec 13, 2017 at 11:40
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Mutli coated UV filters are intended to reduce sun flare - so if thats the effect you are going for, then you may want to consider losing the filter.

Some anecdotal evidence, I (read as: my wife) dropped my 50 mm f/1.4 on a vacation. We had a uv filter on it, and it cracked it in several places, and jammed the lens cap into the filter threading. After some work with a pair of needle nose pliers, we were able to pry it of. Thankfully the lens itself was fine.

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    \$\begingroup\$ a $7 UV filter also saved my $600 18-200mm lens after it was dropped as well. I would never not put some filter on a lens. \$\endgroup\$ Jul 16, 2010 at 2:32
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    \$\begingroup\$ Multi-coated UV filters are not intended to reduce the flare that would be present if the filter wasn't attached. The multi-coating is intended to reduce the amount of flare that the UV filter produces, which is quite a lot. Any UV filter will add flare. \$\endgroup\$ Jul 18, 2010 at 8:59
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    \$\begingroup\$ otoh I had something similar happen (also with a 50mm :) ), but there the filter scrammed so bad it took enough force to remove to permanently damage the threading on the lens. Glass dust from the cracked filter also caused small scratches on the front element, was lucky none got into the lens body... Later another lens fell on its thread, causing a minor chip in the edge of the front element that has no visible effect on the photos produced since. In fact it's now better with chip and no filter than prior without chip but with filter. Suffice to say I no longer use "lens protectors". \$\endgroup\$
    – jwenting
    Mar 30, 2011 at 6:02
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    \$\begingroup\$ The front elements of lenses are thicker and made of denser materials than UV filters. Just because a UV filter was shattered is no proof at all that the front element would have suffered the same fate had the UV filter not been present! \$\endgroup\$
    – Michael C
    Aug 28, 2016 at 22:12
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    \$\begingroup\$ Yes, I am really not a fan of UV filters- I have some fabulously thin and expensives ones as a gift which shattered due to the changing air pressure when flying with them in the cabin. Think of the possible scratches and damage to the front glass on my lenses! I was very relieved to find in this case there was none, but I have not used UV filters since. Sun hoods, on the other hand, are almost always useful, including but not limited to 'bang' protection. \$\endgroup\$
    – user59085
    Sep 12, 2018 at 8:58
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Yes. Adding two additional refractive interfaces will always affect image quality to one degree or another. Putting a flat filter on the front of a lens system will always increase lens flare caused by reflections. The best multi-coated filters will greatly reduce those reflections, but they will not fully eliminate them. The quality of the filter material can also add distortion to the light that passes through it.

One must always consider the optical penalty imposed by adding two more air/glass interfaces into the optical path. Just how detrimental that will be depends on the specific shooting conditions as well as the overall quality of the specific filter and its coatings. For instance, the optical penalty imposed by placing a filter on the front of a lens is more of a consideration when shooting into strong backlighting than it is when shooting with strong lighting sources behind the camera and there are very few specular highlights in the scene. Shooting a night scene with small but bright light sources in the scene will cause ghosting. The extent of the reflections will depend upon the coatings on the filter, the lens' elements, and even the front of the sensor's filter stack.

Whether a UV or other protective filter actually provides a protective benefit is a hotly debated topic. Because a thin flat filter is more likely to shatter than a thicker and differently shaped front element made of different materials, there are cases where a shattered filter may actually increase the amount of damage to a lens' front element by causing multiple scratches.

For more about the overall subject of To filter or not to filter (for lens 'protection'), that is the question, please see the following questions here at Photography at Stack Exchange:

Beyond our site here, there is a good series of blog articles by Roger Cicala, founder and chief lens guru at lensrentals.com, that addresses the issues surrounding using filters for protection. They are presented below in chronological order.

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I have never looked at a picture and said to myself: "Oh wow this picture was so shot with(out) a UV-Filter..." because no one has ever seen the difference. It is just a tool like any other tool. Use it against scratches and if it makes trouble for you in a certain situation remove it from your lens and shoot without it. You won't use your flash every time just because it is attached to your camera, right?

You are usually on the right track using a good UV-Filter because it

  • protects your lens from dust and scratches, scratch the filter and loose 100$ instead of 1000$
  • doesn't notably affect your image quality in conditions where no strong light sources are in front of you
  • it does apparently filter out some nasty UV-Rays, well same here haven't seen them before :-)
  • you want to use a thick UV filter to simulate some vignetting on a wide angle?

But as aforementioned it is not a flawless tool because

  • sometimes you want to use more useful filters like CPL or ND Filter so you have to remove the UV usually
  • you want a slim filter to avoid vignetting on the wide angle side but please get a filter that still allows you to use your standard lens cap otherwise this will turn into a rather annoying trade off
  • keep in mind that you can protect your lens from scratches but not so much from dust with a lens hood also, so maybe it is more useful if you are not shooting with a hood
  • if the light is strong you will have more reflections because with the filter there is another layer prone to all sorts of optical issues. But still, when you are shooting towards the sun that is because you wanted to achieve something special right?
  • more glass to detach means more glass to clean to have perfect conditions. No matter of the quality of glass, it has to be very clean in the first place otherwise all fancy arguments about optics are quite useless.
  • UV filter can be an issue for shooting video. I am not quite sure why, but in a moving picture a slightly dirty, even dusty filter stands out much more than in a still picture, so be extra careful here.

After all I am shooting with UV most of the time because it protects my lens when I am outdoors and some punk runs into me at the traffic lights. Again, when I am shooting pictures I have to think about more crucial things of my composition than the UV filter, because a high quality filter simply does its job - keeping the aforementioned bullet points in mind.

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    \$\begingroup\$ I think some of the other answers here illustrate that people have looked at a picture and seen a difference. \$\endgroup\$
    – mattdm
    May 3, 2011 at 12:10
  • \$\begingroup\$ you want a slim filter to avoid vignetting on the wide angle side but please get a filter that still allows you to use your standard lens cap otherwise this will turn into a rather annoying trade off: Dr.Elch is correct. B+W XS-Pro Digital filters (3.4mm thickness) are designed to accommodate the lens cap, but B+W Slim-Line filters (3mm thickness) are not. See schneideroptics.com/info/faq/bw.htm#qu26. \$\endgroup\$
    – bwDraco
    May 26, 2012 at 20:38
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I use one mainly to protect the lens from dust and scratches.

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    \$\begingroup\$ +1 - I think guarding against dust and lens scratches is an acceptable trade off for some degradation of the image. I'd like to see some studies that show how much degradation of image quality is produced by using a UV filter. \$\endgroup\$
    – Frank Hale
    Feb 23, 2011 at 15:51
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    \$\begingroup\$ -1: Same reason as for Zepplocks answer: you don't address the question. \$\endgroup\$
    – Leonidas
    Apr 18, 2011 at 1:44
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No. It also protects the lens glass from scratches and dust.

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    \$\begingroup\$ technically, anything that gets in the way of the light travelling to the sensor/film will have optical consequences. \$\endgroup\$
    – Rezlaj
    Jul 15, 2010 at 19:51
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    \$\begingroup\$ Agreed wholeheartedly about the use of it for protection. This is a picture of my wife's 10-22mm that I love to use for illustrative purposes: flickr.com/photos/erica_marshall/425731394 \$\endgroup\$
    – esm
    Jul 15, 2010 at 19:55
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    \$\begingroup\$ Yes. There are downsides. \$\endgroup\$ Jul 15, 2010 at 20:19
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    \$\begingroup\$ Still don't understand the downvotes. The question is about REAL downsides. A REAL downside of using a UV filter would be something that prevents you from achieving something. For example using DX lens has a REAL downside: can't be used on full frame cameras or using built-in flash has a REAL downside: hard shadows and washed out faces. I guess what I'm trying to say is that comments are for opinions and downvotes are for WRONG answers. So please read the original post before downvoting. \$\endgroup\$
    – Zepplock
    Mar 30, 2011 at 0:50
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    \$\begingroup\$ you don't answer the question, hence the downvotes. \$\endgroup\$
    – jwenting
    Mar 30, 2011 at 5:58

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