Good Times with Bad Filters

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OK. First and foremost this is a fun post. It is not episode 362 of "Should you put a UV filter on your lens". Some people use them. Some don't. There's not enough bandwidth to ever end that argument.

But here at Lensrentals, we have a ton of filters. We have some really good, very expensive filters. We have some OK, middle of the road filters. And because some customers, uhm, happen to return a very cheap filter in place of the one they were sent, we've obtained some crappy filters. Brand names aren't necessary. If it cost $22 in 77mm size, it's a crappy filter.

Anyway, one of the techs has to clean all those filters, make sure the threads are OK, and test them out. Honestly nobody likes to do it, so it gets put off until we need some filters or there's just nothing else to do. So the other day Kenny is cleaning filters and testing the threads by mounting them one in front of the other until he made a nice mountain of 50 UV filters.

50 UV filters, cleaned and neatly stacked.

Not being the kind of people to let well enough alone, we decided to mount them to a 5D Mk II and 300 f4 we had handy and take a few pictures.

The well protected lens.

And of course see if the filters affected image quality. See if you can tell which images was shot with the 50 UV filters, and which without:

Shot of the building across the parking lot without filters (above) and with 50 UV filters (below). The one with the filters is actually better than I expected.

Of course there's a lot of vignetting and haloing on the full size image:

Compared to no filters

Roger, do you have anything constructive to say, or are you just wasting blog space again?

Yes, actually I do. Fifty filters stacked is pretty ridiculous. But in that stack of 50 filters, as I said, there are some very good ones and some very bad ones. Lets compare a stack of each, shall we?

First, I had Kenny put the worst filters on the top of the stack (all were nonbrand, or brands we know are cheap and bad) and take a picture of the stack at an angle. All were freshly cleaned and if you look straight through them reasonably clear. Like a filter should be. But if you stack them and try to take an angled picture through several layers of them, the results were ugly.

View through a half dozen cheap filters stacked on top of each other. Try counting the filter rings inside the stack.

Yes, I know they don't look clean in the image, but every one of those filters was freshly cleaned, and checked under a light. And if you look straight through them they were pretty clear. Looking at an angle tends to show you the weaknesses of a filter much better than looking straight through it. And remember: most of the light rays coming into the lens are coming in at an angle, not heading directly to the sensor in a straight line.

Now lets compare the stack with the expensive, top of the line filters (B&W, Heliopan, etc.) stacked the same way.

Stack of expensive UV filters one atop the other.

Hmmm. I'm starting to think there might be a difference here. But the proof is in the pudding. Lets modify our original experiment to something only slightly ridiculous. Instead of shooting through 50 filters, lets take the shot through 5 top of the line filters and another through 5 bottom of the line filters.

Here's a 100% crop of a bumper sticker across the parking lot shot first with no filter, second with 5 stacked high end UV filters, and then with 5 stacked low grade UV filters.

100% crops of a bumper sticker shot through no filters, 5 stacked good UV filters, and 5 stacked cheap UV filters.

Now stacking 5 filters doesn't have a ton of real world implications. Most people rarely stack two. But it is a fun demonstration that there really is a difference between good filters and cheap filters.

The good filters do a remarkable job: 5 stacked filters means 10 air-glass interfaces before the light even gets to the lens. That there's only a little bit of image quality loss through all those filters is pretty impressive. This crop is from the center of the image, there's more degradation to the sides, but still, it's an impressive performance. And certainly lends credit to the idea that a high quality, multicoated UV filter has little effect on image quality.

Five bad filters, though, is another thing entirely. I'm completely aware, for those of you who are going to feel the need to point out the obvious, that nobody shoots with 5 UV filters. And I understand that one cheap UV filter wouldn't have nearly as bad an effect on image quality as 5 of them. But I don't think you can disagree that the good (and expensive, I know) filters have much less effect on image quality than the cheap filters.

BTW - before anyone asks, I avoided name brands of cheaper filters for a reason: many filter manufacturers make both pretty good, and pretty bad filters. You can tell the difference by the price or by reading carefully about the number of coatings, etc. A Tihoya $29 "high quality" filter is not the same as a Tihoya $79 "Professional" filter. This wasn't meant to be a filter review, just a fun demonstration of the obvious.

Roger Cicala


June, 2011

215 Responses to “Good Times with Bad Filters”

Rick said:

I can't find one for my 500mm. Should i duct-tape a piece of safety glass on the hood?

tbyrd said:

I never use filters... I understand the argument for 'protecting' the lens but I never understood why anyone would want to put cheap glass in front of their lenses.

BTW, Jeef B's post (above mine) is spot on!!! I hope everyone else uses filters so I can buy your lens from you someday!!!

John Stone said:

I'm a big fan of using high quality filters as protection for my lenses, despite the cost. One of my hobbies is astrophotography. Astrophotography requires long exposures, which means that the lens and camera are exposed to the elements for hours at a time. During the course of this process on cool nights during humid times of year, dew can be a serious problem, or frost in winter. Some lenses are only fully weather sealed when a filter is in place. The first time you have to put a lens in a heating blanket, leave it in hot sun, or use a blow dryer to heat it up to dissipate condensation off of internal lens elements, you quickly take on a more serious attitude about these issues. I often use dew heaters and lint-free towels wrapped around the outside of the lens body to help combat these problems, but sometimes mother nature wins anyway (cable gets unplugged, dew heater battery goes dead, too cold too fast, etc).
Besides astrophotography, I love doing landscape shots. These are often in imperfect weather, on rocky or mountainous terrain with wind, snow, sand, blowing dust, or other environmental challenges. I find it a heck of a lot easier and less nerve racking to remove a UV filter from a $1800 lens to clean it carefully than to have to do the same on the lens itself. I can keep an extra UV filter in my bag that's cleaned and ready to go in case the one on a lens gets soiled. I should mention that I _always_ use the lens hoods on my gear, both to stave off the sand and dust, the dew, and to avoid reflections from bright sun etc. I end up having to clean the lens hood and filters regularly, but my lenses have no scratches on the front elements, yet, and there've been a few times when I would have missed a nice shot if I couldn't have quickly removed a soiled filter and either shot without it, or put on a clean one.
If you shoot without a filter, when the front lens element gets soiled, you have no choice but to either shoot anyway, or stop and try to clean it quickly. Cleaning too quickly/roughly is exactly how a lens coating gets scratched...

Jeff B said:

I never use a filter on any of my fine lenses, including Leica, Canon L, and Nikon. I do however, encourage all others to use them, even if they ruin the images because I might someday buy one of their lenses on the used market and appreciate that many of the old lenses have like new front elements because the original owner never took the filter off :) . Like others that have commented, I have not scratched a front element in more than 30 years of photography and I NEVER shoot with a filter because I want the ultimate contrast my best lenses can provide.

Geert said:

I won't go into the image quality part, but there are two practical reasons to be weary about UV filters:

1. A high quality UV filter often is about as expensive as a new front element

2. A filter damages MUCH easier than a front element.

I find a decent lens hood works very well for protecting a lens from accidental bumps and knocks.

Paul said:

Whoops, I should have provided an example: http://www.betterphoto.com/gallery/dynoGallDetail.asp?photoID=11517631&catID=45873

This was shot with NO filters. Had I had a UV I would have had flare all over the place. The sharpness and tone and contrast come from that Canon element staying pure as it inhales the light. Please destroy all UV filters, lol!

Wait, one exception: if you're at the coast and it's windy and sand and sea spray are flying all over, yes, you want to truly protect that lens in that situation.

SW said:

My two bits: believing that more glass surface means more distortion, I ran a series of personal test shots off a tripod using a 24-105L Canon 77mm lens: lens only, UV Hoya filter (more expensive) and UV Quantary filter (cheaper). The shots were long-distance across an urban valley.

The with-filter shots were sharper than without. The Hoya edged out the Quantary by a tad.

Paul said:

I only use a CPL or an ND when I need a CPL or ND. The "protection filter" thing started in film days as a great way to make a profit because stores didn't really on lenses. Today there are 10x more customers.

Anyway, go get your UV protection filters and toss them into the lake. They do a very bad thing to your inage: attract flare like bees to honey. That's a MUCH bigger problem with digital due to sensor sensitivity.

Protect your lens with th ebest thing available, a lens hood (glad all L lenses come with one). Besides the glass being set way back, you are guarded from any stray light across your lens which causes flare and decreases contrast. My $2500 Canon 70-200mm/2.8 is insanely good at transmitting contrast to the sensor, BUT ONLY WITH A LENS HOOD IN PLACE. If I ruin it with even a "good" UV, then what's the point? Better to go buy a $300 Sigma.

Last thought: you might ask "But what about shooting in the daytime at high elevation, there's haze, don't I want to remove that with a UV filter?" Answer: The problem is not the midday haze, the problem is that you are shooting at midday. If you need a UV filter, you're simple shooting at the wrong time of the day. If you want top-level photos, it is ALL about the light and the quality of your glass. If you want to shoot at midday, get a Point-n-Shoot to record your memories. But for a pro lens, destroy UV filters forever, attach your hood (YES, even indoors) and shoot when light is gorgeous, and you will succeed.

Antonio said:

Great article.

I have never used UV filters (I use others that are useful for what I want to obtain). For protecting the lens I use something I call a "lens cap" :-) 20+ years, never have had damaged a lens.

The UV filter thing seemed to me like something the store guy tells you and then gets to be "general knowledge". Everytime I bought a lens, they wanted to stick a UV filter on it. No thanks, do not see the use of it, to protect the lens they say, no thanks, I will take the risk. And this article shows it is even worse to use them, you spend $1000 on a lens for the little extra sharpness, throw a UV filter and the reason to spend that amount of money is gone.

Frank Bosco said:

I use Leica UVAs, B&W UVs and Hoya HMC UV(0)s on my Leicas, Pentax's and Nikons......not a dimes worth of difference between them....On my Rolleiflex, I can't see the difference between no filter and the Rollei U-V Bayonet II....so my working assumption is that one UV filter has no effect no matter which one.....

Rich Gibson said:

Up till recently I did not use protection filters. I switched recently to using them. On a trip I was putting a sling mounted D700 over my shoulder but the sling slipped through my fingers and the camera and 17-35 dropped to the floor in a store. Gulp! The protection filter absorbed the drop and bent onto the lens sticking fast to it. The shock passed into my 17-35 and broke it. I'm out the filter and several hundred dollars for repairing the lens.

No I didn't have the hood on the lens; a lesson I will never forget.


Craig Kozloski said:

More evidence to continue using a lens cap and hood. Not a single scratch in over 30 years.

Somewhere on the web is a page with photos taken with badly scratched front elements. Guess what? Most of the images looked great. The worst case for most scratches is reduced resale value.

Tord S Eriksson said:

I do mostly use UV filters, and if I could afford it, only Heliopan! But some lenses work better without - taking shots of the moon improved without, but Heliopan's marvel that blocks both IR and UV cost as much as good used lens!

Jessica said:

Personally, I prefer to leave a polarizer filter on my lenses as the "protective" filter. Since I usually want that on the lens for the photo itself anyway, it's just easier to leave there and take it off when I don't want it on.

Steve G said:

I once picke up a 70-200 Minolta 'beercan' tele for free because the guy 'never got a good result with it'

Long story short - I took off the 'store brand' UV filter on the front and - shazam - excellent results...

Mike said:

More than one person has said they use a filter for protection, but remove the filter before taking the photo.

I do the same thing, but I use a lens cap for protection, not a filter.

Mark said:

I was always taught to spend the money on the lens. Protect it with a filter, but when it comes time to shoot take it off. Lenses are expensive, why put even a $100 UV filter on a $1200 lens....doesn't make any sense to me.

Terry Byford said:

A great fun experiment. I have always used a filter purely for lens protection. Get scratches on that front lens element and then shoot with a light source either directly or obliquely shining into it and you can often say "goodbye" to decent pics from your expensive lens.
A few years ago I bought a Sony R1 for its fantastic Zeiss lens. Thinking I could save money, as it takes a 67mm filter, I bought cheaply only to be horrified when pointing the camera out of a window to see a staggering amount of reflections that the filter's coating couldn't suppress. I took the filter back and waited 3 weeks whilst the store sourced a "proper" filter for me at 5x the price. But it worked. Nuff said, I think.

dlj said:

I stopped using UV filters when I went digital years ago, and haven't regretted it other than *one* trip, at very high altitude, where the UV created a noticeable haze increase with distance. You don't get many opportunities like that, so remember that the default UV reduction on modern digital cameras doesn't handle all amounts of UV, just the most common amounts. Oddly, other trips to high altitude (but not as high altitude) didn't show the haze, so you have to be really up there (4-5+ km) to experience it.

jean said:

I use now the cheapest uv filter 5$ from ebay for all my lenses, then when on a shoot I unscrew the filter take the shots and rescrew it to maximise quality. I paid 150$ in the past on a b&w and it would everytime get a little blurry, on all lenses L,prime,zoom. returned it to check and it was according to them the normal standard. unless weather
condition is bad or in a place with lots of people, the only use for me is to protect the front element in case my cap goes off.

RHB said:

How do the Ultraviolet (UV) Pro 1 Digital Multi-Coated Filters and Ultraviolet Clear Pro 1 Digital Multi-Coated Filters stack up against the more expensive B&W tested above? I've read the Hoya Digital Multi-Coated are supposed to be just as good. That's mostly what I've been using and I certainly don't notice any issues. I've used B&W but I don't like the caps on their thin filters and their polarizers are bumpy and hard to clean. So I've stuck with Hoya and like the price better as well.

LensRentals Employee

Roger Cicala said:

Akira, the price varies depending on the lens. Some are more. Some quite a bit less (the Canon 70-200 f4 for example, the front element is $83). In general wide angle lenses have more expensive front elements.

sinan said:

Creative experiment, thank you Roger.

Akira said:

Can you get a front element replaced for $150 as Roger states? In that case, the cost of a good filter doesn't make a whole lot of sense except that you're without the lens during the repair. Also, in the case of a drop, I think that the filter ring protects the barrel, which is why the filter shatters when dropped like that (it happened to me when a lens rolled out of my bag). A barrel replacement will be more than $150. Of course a lens hood would prevent that problem. I like to use a (low-profile) filter on my 10-22mm though. The front element moves within the barrel, which means that the inner parts of the barrel can be exposed. Also, the front element isn't a flat piece of glass like it is on most lenses.

Michael said:

There seems to be a lot of debate on whether or not a filter really does protect a lens, and a lot of anecdotal evidence supporting both those who say either that one does or that it doesn't matter. I won't join that debate.

I will point out, however, that whenever I see a lens for sale on ebay, the condition of the front lens element is very frequently an issue (whether advertised by the seller or inquired upon by the buyer), and that lenses with even very small scratches on the front lens element seem to sell for somewhat less than those which don't. Indeed, a selling point often seems to be whether or not that front element was protected by a filter during the ownership of the lens.

What I take from this is that whether or not a single UV filter actually does matter when it comes to actual lens protection, it may, on the other hand, count for a great deal when it comes time to sell the lens, especially for more expensive lenses where the buyer is likely to be more critical of the lenses' condition. When it comes to selling, buyer perception is everything, whether it is grounded in practically reality or not.

Paul Lazzaro said:

Back in the analogue seventies, I worked in a camera store, and we used to check filter quality by holding them almost horizontal, then looking at some distant object through the maximum thickness of glass.

The amount of 'rippling' was often substantial, and with ample stocks to look at/compare in moments of boredom it was fairly clear to see which big brands at the time were buying their glass from the cheapies and re-branding it!

Nikon and Leica were always first class, and I recall Hoya was the first independent whose stuff also measured up well, and were also early into multicoating their range/slim mounts as well.

It was all too easy to jam stacks together, so a little hacksaw notch diagonally across the front and back rings meant you could
always separate them. Today's useless fact!

Rol said:

Good article Roger and supplementary explanation JeffT (June 16, 2011 at 7:49 AM).

I think some of the reasoning specifically about the use of UV filters could be a hang over from film. I have certainly used quality UV filters with film to fractionally 'warm' a picture by reducing the high end blues.

As for lens protection, when out and about, multi-coated lenses (compared to a filter) are tricky to keep clean, so I've often used a UV or 'skylight' filter for convenience. A couple of times the filter has taken a scrap, so I've been able to replace it and continue shooting.

Interestingly, the only lens I have where the front element has been damaged, was damaged whilst being repaired by a professional service some years back. Unfortunately as it was expensive and discontinued many years ago, I've as yet not found a suitable replacement...

Jure said:

I use only cheap filters. You must admit that by using only one filter it is almost impossible to see the diference and that 99,99999% of hobby photographers use more only one or - better - none.
:o )

Robin said:

The real comparison is between one expensive new filter and one apparently perfect 20 year old Hoya bought at a camera fair for 2 or 3 pounds or dollars which is the only sort of filter many people ever use. Pity this key test wasn't done.
What was interesting was how bad 5 expensive filters were. Many zoom lenses consist of 15 or more elements and yet give state of the art contrast. So what's the problem - the coating or the flat sufaces? Pentax used to make a slightly curved 'ghostless' UV filter, convex at the front and concave at the rear to combat known defects from the use of flat glass surfaces.
The main purpose of a filter used to be to avoid fingerprints/rain etc reaching the front lens element and subsequent cleaning damaging the coating. Also some lenses had 'cold' transmission (which really mattered when you were using Kodachrome) and many photographers wanted to warm them up with 1A or 1B skylights.

Uncle Toopula said:

I want to see multiple choice 100% photo crops where the viewer has to pick a) shot without a filter b) shot w/ a single b+w UV c) shot w/ a single el cheapo UV. Finally, d) shot after front element is scratched up.

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