Equipment

Yet Another Post About My Issues With UV Filters

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Published May 16, 2017

This is a good filter. It is NOT the filter that was returned with the lens in question. Roger Cicala

Yes, I’m sick of filter articles, too. But I come today not to educate you, but to mock others. Because yes, people continue to try to save a few bucks by putting a cheap filter in front of their $1,000 lens. And also because they buy what they think are good filters off of Fleabay or some used place and these filters aren’t what they think. This can particularly happen when you purchase a brand that makes different filters of differing quality.

How bad can it be, you ask? Well, today we’ll show you. Because someone had a 70-200mm f/2.8 lens that had been nice and sharp and then returned it because it suddenly got soft. They were kind enough to return it with their protective filter in place.

So the first thing we did, as we always do, was put the lens on OLAF, which is simply an array of collimated 5-micron pinholes. A good lens should show and an array of small dots or circles. But this lens showed an array of glaring star flare thingies.

200mm with the filter in place. Olaf Optical Testing, 2017

 

No question, the customer was right, images from that lens had to be soft. But, just for completeness, we removed the filter, even though its label indicated it was a high-quality filter. Without the filter, it looked just like it should have.

200mm without the filter.  Olaf Optical Testing, 2017

 

Another thing we do on OLAF is slightly defocusing the image. In a nicely centered lens, the dots should turn into regular circles. This is that same lens above, just slightly defocused and looking just like we’d expect.

Olaf Optical Testing, 2017

 

Then we put the filter back on without changing anything else.

Olaf Optical Testing, 2017

 

If you have the slightest bit of visual imagination, you can probably figure out that there would be some bizarre, ugly bokeh with the filter on this lens. If you’re an optical geek, you might think that perhaps this filter isn’t really flat optical glass, it’s cheap sheet glass with a bit of wavy thickness.

There are a couple of things I should mention, just for completeness. We repeated the test with other copies of the same lens using the customer’s filter, and the results were identical. We also put a high-quality filter on the client’s lens and while there was a bit of blurring of the pinholes (longer lenses are more sensitive to filters), it was very minor.

So, if you want to know how much a filter that looks shiny and clear when you look through it can affect your images if it’s a cheap POS, well, there you go. Because if you looked at this filter, and looked through this filter, it would look just fine.

And another caution, just because a filter has a name brand on the side you recognize doesn’t mean it’s a good filter. For example, you can buy Tiffen or Hoya brand 77mm protective filters for $15-$18, or a better quality one of the same brand for about $35 , or top-quality for $70+ at a reputable dealer. The $15 filter is not the same quality as the $70 even though they both have the same brand on the side. And if you buy from less reputable dealers all bets are off because knock off cases for the higher priced filters are easy to obtain and the filter inside might not be what you think it is.

To learn more about what I think about UV filters in general, read my article on the topic here. There are circumstances where good-quality UV or clear filters are really a good idea. But there are no circumstances where a low-quality filter is a good idea. None.

 

Roger Cicala and Aaron Closz

Lensrentals.com

May, 2017

 

Author: Roger Cicala

I’m Roger and I am the founder of Lensrentals.com. Hailed as one of the optic nerds here, I enjoy shooting collimated light through 30X microscope objectives in my spare time. When I do take real pictures I like using something different: a Medium format, or Pentax K1, or a Sony RX1R.

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  • Thom Hogan

    That’s a reasonable approach, IMHO. I use protective filters around volcanoes, for example, because I really don’t want what’s in the air to get on the front element of the lens: it can scratch and it can directly impact the coating. Sea spray in some areas would be another one where protection is a good idea.

  • Thom Hogan

    No, a lens hood doesn’t do that. But go back and read my 14-24mm f/2.8 review. I subjected that lens to a lot of physical abuse. In the motorcycle shots I ended up with the built-in lens hood holding a lot of mud. Cleaned the lens and it’s perfectly fine. Rubbing the coating off modern lenses is actually difficult to do (though it can be done).

    Meanwhile, I’m with Roger on this one: there’s not a single “protective filter” I’ve tried that doesn’t change the optical properties in a way that is negative. And that includes some high-priced ones. If you don’t care about the optical quality in your shots, then buy cheaper lenses! Don’t put a protective filter on it. With all the money you save by doing that you can easily afford to replace it should the worst happen.

  • Mike King

    I teach photography and in the last year I have had to remove the broken bits of cheap filters from expensive lenses on four separate occasions. Four times. It’s a pretty small enrollment in our program, too. And did I mention–four times? Oh yeah, for novice photographers, replacing a cheap filter beats replacing an expensive lens. I always suggest they replace said sad, broken, cheap filter with one of better quality for the next go around.

  • LensTip reported a while ago that the cheap Tiffens are worse than a clean sheet of window glass. So it really wouldn’t surprise me if this was a genuine product.

  • Jesse Lee

    Thanks for the clearly-understandable article. Those images made the message abundantly “clear,” no pun intended.

  • Jesse Lee

    I presume you’ve been buying lenses often, too? Unless you only shoot indoors.

  • t_linn

    Don’t get me wrong. I’m pro-filter. But I haven’t seen a $30 filter that I would trust.

  • Laud Farter

    Cheapo Tiffen is absolute crap. I borrowed a Leica 35 ‘Cron with a Tiffen UV filter and the loss of contrast, weird softening, and some “je n’ais sais quoi” were clearly visible. Also saw similar degradation from cheapo Tiffen on my Nikons. You could A/B it, it was so bad.

    I also bought a used B+W UV/IR 486 that gave me weird colors on my M8; it had B+W markings but on the side, not the inside like their other filters. And then there was the Nikon UV that seemed a bit off, and the multicoating was different color than other Nikon filters I have. Don’t buy new or used filters without a good return policy.

  • Edmond Wong

    How can you tell if it’s one side or both?

  • Jumping Pearl

    my images with and without Hoya UV filter are indistinguishable, and the benefit of keeping the front lens element clean in dirty environments is great

    this idea that there are tons of bad UV filters out there is baloney, yes some exist, but most peple know you shouldn’t buy a $10 filter

    most people are buying the $30-$50 hoya filters from amazon and they offer amazing protection for environments with lots of particles, dust, sand or smog

    cleaning a $1000 lens with the risk of removing coating = nightmare
    cleaning a $30 UV filter = not a problem

  • Jumping Pearl

    a lens hood doesn’t protect against dirt / sand / smog particles

    why do people seem incapable of understanding the difference

    I’ve rather clean a $30 UV filter than rubbing off the coating on a $1000 lens

  • The3o5Flyguy

    I was a fool if to think adding a $10 piece of glass infront of a $1000+ piece of glass will produce a sharp image…. I took my filter off my lens once to clean off a smuge forgot to put it back on. I went shooting and noticed the images were sharper than they had ever been. Since then, my filters have been colecting dust

  • Patrick Chase

    The other article only shows before/after results from a good filter on a 50/1.2 (42 mm entrance pupil), which is a relatively filter-insensitive geometry. That specific lens doesn’t have terribly high MTF to begin with, which makes it difficult to spot modest attenuations from the filter (a 10% loss is a lot harder to see when you’re starting at 20% than when you’re starting at 80%).

    What would be nice to see if possible is a similar comparison using a 200/2.8, 400/5.6, or similar. Good examples of such lenses have pretty high MTF without the filter, which makes the degradation more noticeable (both visually and in measurements). In addition their large entrance pupils mean that they will be more sensitive to things like flatness across the entire filter.

    FWIW I mostly use B+W XS-Pros now (same filter pictured in this article). I also have a couple Hoya HD3s (their top of the line filter) and an eye-wateringly expensive Heliopan SH-PMC. They all seem to work, with the B+Ws being the cheapest of the lot.

  • Ian

    Holy *bleep* Lensrentalman! That’s amazing to see that it affects it that much and reminds me of the old saying, “If you can’t afford the hub caps, you can’t afford the car.” Thanks as always for the informative and entertaining post!

  • That would be correct 🙂

  • DrJon

    One of the things that annoys me with all but a tiny number of UV and Protection filters is reflections from the inside of the filter for Night shots with bright lights in them. I believe it’s the lit-up sensor that is making the reflection back to the filter. I found the Hoya HD ones to be unacceptable (to me) and really only the posh B+W ones work well for me. The other answer is to remember to remove the filter for Night work, of course.

  • BattleBrat

    I use heliopan UV/IR Digital cut filters, and my lenses spit out razor sharp images so I guess I’m ok laughs

  • Eddy Kamera

    So I assume that filters of other types such as ND and CPL are also not created equal? I have a couple of cheap ND filters.

  • rb763

    I started using filters when I put a scratch on one of my lens’ front elements. So today after reading this, I thought I would try a few shots without the filter on my Canon 70-300 L lens which I was using on my Sony a6500. I never even got to the image quality comparison because the first thing I noticed was how much removing the filter improved the autofocus performance. Night and day!

  • Max Rockbin

    I discovered your blog a couple years ago after googling for whether UV filters were worthwhile. I’ve been reading you ever since. So (at least from my point of view), you’re not just spitting in the wind.

  • Steve Oakley

    only my 17-55 has a UV filter on it. its for more run and gun stuff and gets exposed to a lot of dust, handling ( fingerprints ) and potentially rain. trashed a filter once ( rock hit ) already so it was a cheap investment. the rest of my glass almost never has a UV filter because of cost and the potential issues the extra surface adds. One could get a 82+MM filter and a set of adapters to go smaller for those once in a great while times when some protection is in order.

  • Pete Myers

    Hi Brandon—I will defer to Roger for explanation, as I am just a guest on his Blog. Suffice it to say, I hate plastic filter threads, and I think it is a poor reflection upon the industry.
    Pete

  • Brandon Dube

    Why even keep it relative? It takes ~1/5lb of optical glass to make the filter and these are all made of BK-7 at $10/lb. The finished and coated element in a good UV filter would be less than $10 at volume. A more complex filter is not significantly more expensive.

  • Mike Barrett

    Here is my rant with filters…. Pricing… Let me see if I have this right. Take a look at the thickness and geometry of the glass elements of a modern lens, the complexity of zoom rings, centering, shims, focus rings, coatings, etc, etc.

    And then on a per piece of glass basis, a single piece of thin (easier to make clear, etc) glass costs 2-3x that of piece of glass in the body of a lens. (ps I used to work for a glass man’f trust me on the then vs. thick chunks of glass). It isn’t the cost of the glass, the precision in which the shapes are ground (flat vs. complex curves on both sides) that drive up the price of the filter… 🙂

    Capitalism at play…. certainly…. and stupidity that we will buy 1 piece of glass for 10%, 20% of the cost of a 23 element lens. These filters fit on lenses from all man’f, if anything they should have a better economy of scale. Look at how many lenses have 77 or 82 mm threads, how many copies of Canon lens element 4 in the xx-yy zoom does Canon make vs. a filter maker’s 77 mm UV, Clear filter…. I suspect far more then C,N,Z,L,S, etc make of any one element of their zz-yy zoom. Yet the lens maker can make several more, align, shim, etc and on a per piece of glass basis deliver a superior product.

    Ok rant over.

  • Brandon Dube

    If you put a true window in front of a lens (both surfaces very flat), it doesn’t matter how you orient it, there will be no impact on the in-focus image. If you have a cheap filter that isn’t actually flat on both sides, its orientation will matter.

  • Colorado Kid

    Ed, you don’t have to get that close, get a tele if there’s danger. 🙂

  • Pete Myers

    Hi Carleton:

    You are asking a good question. High-end filters are always made of brass, with brass threads. Using metal threads against plastic tends to quickly wear the plastic, and the thread becomes “sloppy.” Remember, we are adding an optical element to the lens, so it has to be perfectly aligned with the front lens. Any play in the threads and mis-alignment will lead to an astigmatism in the lens response. As Roger and his crews have grandly demonstrated, it does not take much to greatly effect the lens response.

    Also, plastic is injection molded, and there tends to be a bit of heat warp and variation in tolerances as a byproduct of the process. Brass threads are machine cut, and particularly with brass tend to be a precision component—like the movement of a fine analog watch.

    For those of us that do monochrome work not derived from bayer color sensors, contrast filters are an essential and an every day component of our work. We are constantly changing them.

    Pete

  • Nick Spiker

    On another note, why do people insist on UV filters? Silicon is not very sensitive to UV, plus the internal camera filter usually blocks it. All of the UV filters I have tested don’t even block UV anyway. I think the idea is quite pointless and irritating when you actually need to block UV. Protective filters on the other hand, are a good investment, and should be considered in the budget.

  • Les

    Al,

    re: “my long lens won’t focus with polarizing filters”
    The first thought that comes to mind is that you are using a regular polarizer instead of a circular polarizer.

  • DilbertJ

    He has another article linked where he shows that info. The purpose of this article is to reinforce a standing opinion that cheap filters are no good.

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