Reinaldokool Loc: San Rafael, CA

Good multi-coated filters really don't degrade the image. Cheap ones may. I don't see any difference. I use Hoya filters and they do fine. Use a lens hood anyway to reduce flair from lights in front of you. But that's true whether you use a filter or not.

Dik

Canon says to use a filter to make it's L lenses weather sealed.

ralphc4176 Loc: Conyers, GA

I have been using UV/skylight filters on every lens I own for decades. I buy premium, multi-coated filters; I haven't noticed any more tendency to flare than any of my premium lenses (Fuji, Olympus and Minolta in film cameras, Canon and Sony in digital). That filter protects the front element of the lens from mechanical damage--so far, a filter has saved one lens. I have taken photos with and without a UV filter, and I've never noticed a difference.

RichardSM Loc: Back in Texas

Hi jerry

Thanks for both of thoses sites it was a good refresher for me. I don't us UV filters on any of my lenses either for protection the lens cap or hood do the best job for me. There was a time I did use them when I shot film B+W UV pro line very expensive back then around $90.00 today they cost around $395.00.

tjphxaz Loc: Phoenix, AZ

I understand modern DSLR camera sensors are built not to be susceptible to UV effects. I use Nikon clear lens filters for protection against drops and bumps. Plenty of bumps over the years and just one drop all of which have been handled by the filter saving the lens.

John Howard Loc: SW Florida and Blue Ridge Mountains of NC.

I have a related question - please excuse the interruption.
This year I took the plunge and purchased the Nikon 200-400, which has the slot near the backside for filters. It came with a Nikon UV filter. I have left it in because it is attached to the bracket that covers the slot - ie, no filter means the slot is open to dust etc.

I noticed in this thread that shooting in to light with a uv filter can cause flair. Could this be causing problems with shots of the full moon? Is there a part I can buy to close the slot without the filter?

Dik

The rear filter in the Nikon 200-400 is part of the lens's optical formula and should always be used unless a different filter is put in it's place.

ricardo7 Loc: Washington, DC - Santiago, Chile

I would love to see a side-by-side photo comparison that shows the image quality degradation caused by using a UV filter. Anyone?

oldtigger Loc: Roanoke Virginia-USA

Coming up with the images is simple but what are you going to view them with?

Architect1776 Loc: In my mind

I fully agree with this in some situations. I have had a very expensive lens saved by the filter. Also personally know several others who this is the case.
That said I seldom use a clear filter but always have the rigid hood in place for protection.
But as I said in some environments I use the clear filter for salt spray, excessive dust etc.

mwsilvers Loc: Central New Jersey

It is true that Canon recommends the use of filters to dust and weather seal many, but not all of its L lenses. However, there are a number of L lenses that don't contain sealing gaskets and adding a filter will not provide that benefit. In any case, that's not the same as recommending them for protection of the front element. As far as I'm aware there is no general statement by Canon, Nikon or other camera manufacturers that the use of filters will protect the front elements of a lens from damage. Perhaps someone can enlighten me on that.

jimmya Loc: Phoenix

I have four Canon lenses in my t3i bag. Each has its own
UV filter installed. They make virtually no difference in the results but do protect that all important front elements.

houdel Loc: Chase, Michigan USA

I would state this as "UV filters are GENERALLY not needed because digital sensors are not as susceptible to UV radiation as film was".

Many folks in photography forums will offer the opinion that digital sensors are not sensitive to UV radiation. That is simply not correct. The silicon photosensors which make up the sensor are sensitive to radiation from 190 nm to 1100 nm, which includes UV, visible light and IR radiation. While the BARE sensor is sensitive to UV, that sensitivity is diminished by three factors: UV is absorbed by glass, so most of of the UV is absorbed passing through the lens on the way to the sensor; the filter array atop the sensor provides significant UV and IR filtration; and the sensor itself is least sensitive to blue light, which is at the end of the visible spectrum where UV occurs.

However the devil is in the details. The UV spectrum "ends" at 400 nm and the visible light spectrum "begins" at 400 nm, but in terms of photo response it is not a sharp cutoff, and as stated, the camera sensor is least sensitive to visible light at this end of the spectrum. Further, the UV filter does not have a sharp cutoff either. To minimize cutting off any of the blue light at the beginning of the visible spectrum, the filter array has to be designed to pass some UV at the very lower edge of the visible spectrum. Thus the filter array does pass a small amount of UV radiation.

The last time I researched this topic I found a scientific paper which discussed this issue to great detail, which unfortunately I did not bookmark and have been unable to find since. The bottom line was that all digital camera sensors are susceptible to UV to some degree and even ranked the relative susceptibility of CCD, Bayer and Foveon sensors. However, in most cases, the susceptibility to UV is so slight as to be insignificant for most purposes. But if you need to be convinced, get a Wratten 18A filter and take some pictures through it. A Wratten 18A filter blocks visible light but transmits UV. Since all the visible light will be blocked, you will need to increase exposure, but you can take a UV photograph with a standard digital camera. And yes a Wratten 18A will transmit a small amount of IR radiation, but the intensity is 4-5 stops less than for UV so for all intents you have a UV photo. So while the sensor itself is sensitive to UV, the lens and filter array will remove MOST but not all of the UV before it reaches the sensor. The UV absorbing filter does not have a sharp enough cut-off to absorb all of the near UV without also absorbing some of the far blue visible light, so some amount of UV is passed through to the sensor to preclude cut-off of the visible blue light.

There are a couple of situations where a UV filter can be beneficial. One is at high altitudes where the ambient UV radiation is much higher than at lower elevations, or on bright hazy days when the UV is scattered by atmospheric particulate which causes reduced contrast and detail and also affects the color of foliage. Most camera manufacturers do not mention this but the Nikon Knowledge Database article "Using Nikon filters with Nikon DSLRs" does include the following statement: "While invisible to the naked eye, ultraviolet light can reduce contrast and detail".

Do UV filters affect exposure? No. Even the worst UV filters have a light transmissivity in the range of 96%, the better filters are upwards of >97.5%. Considering that a full F-stop is a 50% change in the amount of light, a UV filter has no meaningful impact on exposure.

Do UV filters degrade image quality? Some filters (not necessarily the cheapest either) yes, definately. Better filters may depending on the scene. The better multi-coated filters generally have no significant impact on IQ. The exception is when photographing into the sun they may increase sun flare. See the first link below for a very thorough, if lengthy, study which tested and rates many of the more common UV filters.

Will a UV filter protect my lens? In certain circumstances both a filter and a hood can offer some degree of protection for your lens. I have in my possession two damaged filters (not of my doing; one was damaged on a lens in transit and one bought on the lens from the previous owner). The glass of both filters was shattered; filter glass is fairly tough stuff so I have to believe that that the force absorbed by the filter was enough to have potentially caused some damage to the lens if the filter was not there.

Neither a hood nor a filter will provide absolute protection, especially on a cheaper lens which is likely to be less sturdy and less able to withstand impact damage. However a hood will provide some protection particularly if you bump something. A filter will provide some protection from blowing sand or water, a small rock blown by the wind or thrown up by a passing vehicle, or a sharp twig you didn't see while maneuvering for a shot. Even if the object didn't have enough force to damage the lens glass it still could mar the coating on the front element. A filter will also protect against overzealous or careless lens cleaning, such as missing a spec of grit on your lens when wiping smudges off. Replacing a filter is a lot cheaper than replacing a front element.

Should I use a UV or clear protective filter? Your call. There are some good reasons why you should and some reasons why you shouldn't. I have a hood and UV filter on my lenses all the time. If I am in a situation where I feel the filter will be a detriment it only takes a few seconds to remove it. Do whatever you feel is right for you. Following are few links to help you decide.

http://www.lenstip.com/113.1-article-UV_filters_test_Introduction.html

http://photo.stackexchange.com/questions/2262/are-digital-sensors-sensitive-to-uv

http://www.alt-vision.com/documentation/5301A-25.pdf

mwsilvers Loc: Central New Jersey

How do you know the filter actually protected anything? Even if the very thin glass on a filter broke, it doesn't mean the extremely robust glass of the front element would have. When people report on front elements that were damaged due to a lack of a filter for protection, again this is anecdotal evidence since there is no way to know whether in a accident bad enough to actually damage a front element the thin filter glass would have actually provided any protection. I'd personally be more worried about he sharp shards of broken filter glass scratching the front element coating. I use a lens hood on all my lenses. Its main purpose is to control flare, but it protects lens from impact damage far more then any thin glass filter ever could.

Someone recently likened the use of protective filters on lenses to the use of helmets by football players and NASCAR drivers. Last time I looked, those helmets were not made of very thin brittle glass. Now, if someone comes up with filters made of transparent Kevlar that don't degrade the image or cause flare, I may revisit my opinion on the effectiveness of filters for protection.

mwsilvers Loc: Central New Jersey

Do you know from personal experience they actually protect your front elements from damage, or is it more likely you are hoping they will give your lenses that protection. For those of us who are risk averse, that hope is certainly a legitimate reason to use them. In my experience protective filters do occasionally provide a benefit. On some weather sealed Canon L lenses they complete the seal, and in certain adverse conditions like strongly blowing sand they MAY provide some protection for the front element costing. But other than that, I have seen no evidence that they actually provide any real protection.

I once used filters on all my lenses as a kind of insurance when I started out, mostly because the camera store salesmen told me I needed them for protection. Being risk averse, I also used to buy extended warranties on everything for the same reason. Over time I realized that both are generally unnecessary and I haven't bought or used a protective filter or an extended warranty for years, and have not suffered as a result. Things like filters (or extended warranties) are high profit items which is why salesmen push both of them. If you want real protection for your lenses consider using lens hoods.