To UV Filter or Not to UV Filter? Do Filters on Your Lenses Hurt Your Photos?

To UV Filter or Not to UV Filter? Do Filters on Your Lenses Hurt Your Photos?

In the ongoing debate of filtered versus naked lenses, Roger Cicala makes a compelling argument over on his Lensrentals blog as to why, when it comes to filters, you either go big or you don’t go at all.In his post he talks about a customer who complained about a “soft” lens – and it turns out that it was the customer’s protective filter that was the cause of the issue. He figured it out because the customer returned the lens with the filter attached.

Cicala shows before and after tests done that show the difference between a filterless lens, and then talks about the differences between filters that use optical glass and cheaper sheet glass. He tested multiple copies of the lenses in question with the same filter, and the results were the same the cheap filter hurt the image quality out of the lens. This isn’t a surprise – Cicala is known for his meticulous tests and lens teardowns, so it’s a safe to say he knows what he’s talking about here. He talks about certain cases where you'd want to use quality filters, and others where you'd want none at all.

In a completely informal test using a B+W MRC filter on a Canon EF 85mm f/1.8 USM lens, I shot these photos below directly into a light source to see what the differences would be – take a look for yourself:

The UV filter on the lens caused flaring problems in this photo.

The UV filter on the lens caused flaring problems in this photo.

Without the UV filter on the lens, the flaring is gone.

Without the UV filter on the lens, the flaring is gone.

There seemed to be some flaring (the blue circle in his head) and some slight color differences. He (and I) moved slightly in each shot, but you can see how the filter affected the shots. Sharpness seems about the same. Is it enough to make it worth the case to not use filters? Your call – how often are you shooting into the light like this?

I’m firmly in the UV filter camp for two reasons – I always use to leave lens caps on, and then missed moments after raising the camera to my eye like that. Now, I stick a good UV filter (B+W MRC, generally) and I just keep things in my bag lens-cap free, ready to shoot. A small trade-off in my mind for extra flaring.

But the bigger reason is that I’ve actually seen these “protection” filters offer protection. I can’t count the number of times (OK, I can, it was three) students have come to me thinking their lens was destroyed only to find out that they merely broke the filter and the lens underneath was unscathed. I don’t want to think about what they were doing to cause this situation, but in each case the actual glass on the lens remained intact. Admittedly, it was sometimes a source of amusement to perpetuate the myth of the broken lens for a short time.

The protection aspect extends to weather sealing – you’ll often see in lens manuals (y’all read those, right?) that you need a protection filter to complete the weather sealing on a lens. Take this line, from Canon’s EF 16-35mm f/2.8L II USM lens instruction manual - it’s bold, and so it must be serious: “Since the front element of this lens moves when zooming, you need to attach a Canon PROTECT filter sold separately for adequate dust-and-water-resistant performance. Without a filter, the lens is not dust or water resistant.” I can attest to the fact that this is true – though I haven’t tempted fate by venturing out in the rain without a filter.

So, back to the title of this post – to filter, or not to filter? That is the question – what’s your answer? Leave your thoughts in the comments below.

[via Lensrentals]

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27 Comments

David Stephen Kalonick's picture

I'm personally not a fan. 4 stop ND filter to shoot shallow is the only time I use a filter.

I'm not a filter guy... today. I often use polarizers, but that's not what you're talking about. I remember renting a lens from Adorama a few years ago and asking the guy at the desk if they would add a clear or UV filter... his response was, "Why would I put a $40 piece of glass on a $2000 piece of glass and expect it to perform the same way?" He also told me to be a little careful and insure your equipment and you'll be just fine. I guess there is always the, "It's not rare if it happens to you." But I've been lucky so far (38 years), these days the only time I put a clear filter on is to use it as a substrate for some kind of effect, OR if I know I am going into dangerous conditions. For example: stormy beach (sand blaster much?), stage side at a concert (little bits of spittle and other bodily fluids tend to fly around the stage area), construction site for obvious reasons, places where things go boom, etc.

>> his response was, "Why would I put a $40 piece of glass on a $2000 piece of glass and expect it to perform the same way?"

This is because he was what experts call "an idiot".

A $2000 lens may have something like 15 elements plus a complex mechanical construction, motors, etc. The cost per element actually isn't very different to the cost of a filter. And that cost is only an average - with a typical high end lens there will be several very expensive elements with complex grinds and perhaps non-standard glass. Making a piece of flat glass to the same standard is vastly easier and cheaper. A properly made $40 filter will be to the same standard as that $2000 lens.

The Dunning-Kruger effect runs strong in modern photography...

William Howell's picture

Boy I would love to have a UV light modifier for Buff mount. Broncolor has one for 3 or 4 grand, that one is not in the budget!

Edit:
Oops, wrong UV.

im new to photography and i go for a filter. accidents can and do happen. my best lens is insured and dosent have a filter. but as im new to this game i try to keep my other one safe.

Ignace Maenhaut van Lemberge's picture

Always a hood. Never a UV filter.
I crashed a few hoods. Never a lens.

Eduardo Francés's picture

I am with the lens hood camp, it protects a lot more the front element of your lens and it won't deteriorate IQ.

Regardless of the brand or how expensive it is, a filter will deteriorate in some way the IQ, why pay top dollars for a sharp lens then?

In most cases the lens hood will protect the lens more.

>> Regardless of the brand or how expensive it is, a filter will deteriorate in some way the IQ, why pay top dollars for a sharp lens then?

When you say stuff like "in some way" then it's a sign that you don't know what you are talking about.

People who do know what they are talking have actual knowledge and can therefore be reasonably specific. Eg

"A UV filter increases the chances of my getting flare shooting at bright light. But I never do that, so I don't care."

"A UV causes a minute loss in contrast. But with a good one it's less than sample variation between lenses - and a lot less than damage to coating on the front element will cause. So I don't care."

(Both the above are true.)

A US$90 piece of glass to protect a US$1,500 lens sounds like a no brainer, but….

If it is protecting against dust and moisture, why doesn't that come included with the US$1,500 price tag? That is the question. For US$1,400, the Pentax near equivalent (15-30mm 1:2.8 SDM with eight seals) includes all that (as does all of the HD/WR lens from them) and in-camera SR on five axes.

As for protecting against strikes, a petal lens hood should do the trick. (DigitalRev.TV with Kia W has a good video about that). I have an smc KFA 1:1.7 50mm from 1989 which has had its front filter holder knocked off during a protest in 1992. The lens has since had its shares of hits and bangs, (without a filter nor a hood), but it is still in great condition, optically, with no lens scratches (but obvious barrel damage).

But as for UV filtering, many modern Digital cameras are not sensitive to UV light. This includes my DSLR and my smartphone. That is why the Canon Protect filter has no UV filtering listed in its capabilities; not necessary.

I did try a new lens recently and took some night shots at the pier and was appalled at the flare and ghosting of the lights. Turned the camera around, removed the UV filter, shot again. Vast improvement. Showed the owner the difference, he threw away the filter. It does not have to be a bright light, just noticeably brighter than the surroundings.

So I have full weather resistance, dust resistance, scratch & oil resistance, all built into my lenses with no flaring/ghosting, protection against UV haze, and protection against hits by a lens hood (which conveniently doubles as glare protection). If your lens does not come like that, then a protect filter is a good investment but prepare for reduced IQ at high contrast borders.

tl;dr →
The UV filter or Protect filter is NOT worth the price for some lens which has it all but IS JUSTIFIED for pseudo-weather-sealed lenses which require it for full protection when shooting in adverse conditions.

Wasim Ahmad's picture

You raise a good point - if a lens is north of $1000 and has a red ring on it, it's a bit strange it needs a cheap filter to complete weather sealing.

Allen Reid's picture

Speaking of filters...I bought a Tiffen variable ND filter to shoot video with but it's giving me way too much vignetting. Is that common?

Rob Mynard's picture

As mentioned above, UV filtering is not needed on most digital cameras so if you're after a filter for protection you're better off getting a "protection" filter (B+W call them "clear" filters). I believe the main reason stores will suggest a UV filter is because they cost a little more so attract a higher profit margin.
Another + for using a high quality filter is the anti-fog coating. I had various lenses in my kit recently while shooting a wedding in Bali where the humidity was so thick you could smell it. When moving between air-con and outside, all the lenses without a filter instantly fogged up but the filters stayed clean and clear.

hello, perhaps you should read this test wich is very spectacular! http://kurtmunger.com/dirty_lens_articleid35.html

Phil Wright's picture

I don't think UV filters are worth it. Certainly not for 'protection' purposes. ND, Polarising etc, sure in the right place they are invaluable, but just putting a filter on to protect the lens is silly. The anecdote above about a student coming in with a broken filter worried about the lens...well yeah, if you put a cheap bit of glass on the front of a lens and bash it, it's going to break. The lens elements are slightly better produced than a cheap bit of glass. It's very unlikely they'll crack of break if you bash them.

If you need to protect your lens from sand or spit or anything else, use a lens hood.

Finally, a few marks on the front element of a lens will have such a minuscule effect on the image that it won't be noticeable anyway.

I remember borrowing a lens from a colleague a few years ago which had a UV filter (I don't remember if it was a high quality one or not) mounted on it.
So took his lens out over the course of a couple of days and took a variety of different shots and noticed that all photos shot at night had reflections of the light sources that were included in the shot. Rather annoying!

I don't use them unless I know my lens is going into an environment that doesn't favour my lens' well being.

Kian McKellar's picture

The flare on his face is a deal breaker.

Dan Howell's picture

The problem with that idea is the fact that most filters present a flat plane of glass at the front of the lens which is necessarily larger than the front element of any lens and in some case very much forward of front element. That makes the filter actually more susceptible to flare than a lens in some cases.

Kian McKellar's picture

Yeah. Why I don't use filters anymore. Sometimes you don't notice the flaring until post and with video it is much harder to clean.

Kirk Darling's picture

With regard to environmental sealing, that's only for certain lenses (in the Canon line). I do read the manuals, and the only lenses you see Canon advising protective filters for sealing are those specific lenses that require it. It does not apply to those Canon does not specify for it. Canon is not advising protective lenses as a general practice for the purpose of environmental sealing.

The only lens I felt required to use a filter on was my 2 cam Summicron R and that is because Leica said it was needed - so it stayed in. Otherwise good hoods seem to offer enough protection.

Maurice Waters's picture

A few years back I had just finished shooting a wedding, I removed the uv filters for the shoot from my 70-200, after its use put the cap on, placed in bag and went to the next location, got home after reception etc to discover the cap had come loose and with the lens facing down in the bag (backpack) unfortunately there were a few sand / dirt elements in my bag that just happen to sit right on the front element for the walk from location to the other. it was scratched and was probably the first time in ages I had removed the filter and paid the price. it was a perfect storm as to the cap coming off, the sand (seriously a few grains) for this to happen but it was an expensive accident.

Mark James's picture

So is it a filter or a glorified screen/lens protector? I have a lot of nice quality ones and never use them except for the ND filters when they are needed for video in bright light. All of my glass was optimized at the factory and I've never seen a photo a filter has helped make better.

I've always been suspicious of having a filter on for any reason other than actual light filtering, mostly because of discussions like this which don't seem able to convince me of the need for a filter as protection. I've always preferred lens hoods instead. When I was buying a 50mm lens a couple of years ago, the Canon dealer didn't have a hood for it, and recommended I buy a UV filter instead. I did so reluctantly and went out immediately to try out the lens with some twilight street photography. The lens flare was so bad that I never used that or any other UV filter again. Eventually I got a deep aluminium hood for the 50mm that is probably better collision protection than any filter. For my other lenses (a 24mm and an 18-200mm), I've got Hoya polarising filters which I have on whenever I'm shooting outdoors (unless it's in low light), and there's no loss of IQ as far as I can see, and visibly better contrast. They also have hoods on all the time.

I've used Hoya and B+W filters UV or polarizing filters (valued at more than "$40") for landscapes and general shooting, and typically use them (polarizers or UV depending on Sony/Zeiss 50 1.4 Planar and Zeiss Batis 85 1.8 lens) in portrait work. I have never seen any IQ loss and in fact often hear comments about the sharpness and clarity of the images. So, I will check out Roger Cicala's article. Thanks for posting, Wasim.

So I read Roger's article and it seems he is arguing against CHEAP filters. An unidentified guy named David wrote the following which Roger Cicala upvoted and agreed with: "I'm confused by the anti-filter absolutism of some of the comments. I think this excellent article proves indisputably that bad filters can massively degrade image quality. At the same time, Roger has also said, 'A good filter should avoid most (not all, but almost all) effects regarding ghosting, flare, and reflection. It shouldn’t affect sharpness even at the highest level of measurement.' He has shown MTF evidence demonstrating that. And he has pointed out that the rising cost of lens front elements makes the use of filters more of a judgement call. Using or not using filters is a practical balancing act, not a religious belief."

(And I, Scott, will just add that this seems to settle the issue for me. Thanks again, Wasim.)

Wasim Ahmad's picture

I'm a belts-and-suspenders guy I guess - I have a hood and filter on all of my lenses. I haven't noticed any decrease in sharpness (I haven't done head-to-heads, but I figure if I can see the strands of eyelashes and pick out a portrait lighting setup reflecting in my subject's eyes, I'm doing OK). That said, I only put the B+W stuff on, whether I am polarizing, NDing or otherwise. If I see bad flare, I take it off for that photo and it usually solves the problem.

I once bought a generic brand - "KOF Concept" or something like that and it messed up the colors so bad. You could really see it easily.

Working in a camera store, we've seen it all