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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  • Rodger

    promaster HGX filters all day everyday

  • Mike Jackson

    I stopped using UV filters after my first lens drop… somehow the filter scratched the front element on a 2 foot drop. I do consider them when I’m going into an environment that will have flying particulates, but that is very rare.

  • Zos Xavius

    I’ve used the cheap tiffens before and they are nowhere near as bad as this. Unless they have really dropped the ball on quality recently. All the tiffen filters I’ve tried were from the film days.

  • Zos Xavius

    This is what I’ve been saying for years. So nice to see someone prove it with actual tests. Hoods are the way to go.

  • Zog2012

    I was hit 15 times by pucks in NHL, AHL and ECHL arenas. I could shake them off and laugh about them. Once a puck tipped off the glass and hit my in the head and the knee and all the facilities people near me had a laugh. 16th time at the top of the aisle where no pucks go, a fluttering clearing attempt hit the front of my 70-200 VR I and I heard a crunch. Had a metal B + W UV filter on (single coat, I later put the mutli coat one on it). Puck shattered the glass filter and dented the metal ring, but did no visible damage to the lens. There was some focusing lag after so I sent it in under warranty, but there are instances where having a solid, metal high quality filter is a must.

  • I don’t think it’s a problem in general, but phase detection is comparing light paths from opposite sides of the lens, contrast detection, well obviously contrast. I think a BAD filter could interefere with either, but I don’t think a good quality filter would.

  • I’ve never used them or looked so I have no idea.

  • Chaitanya

    Only filters I use are Cpl and nd but thats a necessity while shooting landscapes in tropical India. Also another reason for filter for me is most canon lenses need filter to complete weather sealing and using those lenses in western ghats during monsoons without filter is a fungal nightmare.

  • Carleton Foxx

    I would think plastic threads would be better because they wouldn’t be as apt to get frozen to the lens threads—and even if they did, it would be easier to hacksaw through them. What makes them especially problematic…?

  • David Bateman

    I stoped using filters in 2008, after I purchased a $70 filter to protect a $150 lens. I stoped, looked at possible issues of using filters or not and switched to stop. Even on my lenses over $1000, the hood does the best job for the protection I would need. But I never shoot in dust storms or at the beach, so I know others milage may vary.

  • Carleton Foxx

    What are our thoughts about the Canon- and Nikon-brand clear filters? I have a couple of Nikon NC-Clears and they seem fine, but now I’m not going to be able to sleep at night…

  • Eric Bowles

    I shoot about 35,000 frames per year. Over the past 5 years, I’ve scratched a front element slightly on one lens – cleaning a mud splash that was completely a surprise – and the scratch is very minor. I almost always use a lens hood, and increasingly use a lens cap when I am carrying an extra body or walking through areas that are rough or through brush. I’ve never seen any wear on the coatings – they are surprisingly durable.

  • Al Majauskas

    Thanks Eric. You’re saying uncoated filters cause other problems related to quality. Good to know. I shoot mainly prime on D7000 with my old 24mm 2.8 Nikon with a fairly wide lens hood and I’m going to test picture quality w/o filter and see if the focusing issue is caused by the filter. I might just try shooting without and see if things improve. Another concern is the inevitable finger prints on the actual lens and how to clean without wearing out any coatings. Seems on this you’re between a rock and hard place – protect your lens and suffer quality or damage the lens with dings and scratches keeping it clean. I haven’t put this much thought into such an innocuous little object in 40 years of shooting.

  • Bob Mahar

    So what were the results with a high quality filter? All we have proven is that this filter sucks, not that “better” filters are, optically, better – a photo would have driven the conclusion home. As for longer lenses being more sensitive to filters, what do you mean? Again this is a very “folksy” / subjective way of describing it. “My lens is allergic to cheap filters.” My objection is not that the results or the conclusions are wrong – they are right AFAIK – many cheap filters are horrible. But layering on subjective / non-scientific verbiage is not as helpful as a photo of OLAF with a “good” filter in place. I bet its still not all that great.

  • Pete, that’s an interesting thought because when I first saw these images, I wondered if the filter was cross-threaded and that was causing the problem. That’s why we did comparisons on other lenses and with other filters on this lens.

  • Chik, think this was counterfeit, or ‘replaced glass’ in a Tiffen ring. We stock mid-grade Tiffen protective filters (this was a Tiffen label) and they don’t do anything close to what this did. That being said, I don’t have access to the $15 range Tiffen filter, so it may be they really are like this.

  • Beware of “multi-coated” only on one side because reflections from both sides can degrade quality.

  • Eric Bowles

    Uncoated filters pose an additional set of problems from reflections and flare. As long as you use the lens hood and lens cap, and use a filter with adverse conditions (like blowing sand or salt spray), you’ll be fine. Take a look at Roger’s article about reassessing the risk associated with damaged front elements as the cost of repair is slightly changing the view on protection.

  • Eric, I think I’d use a longer lens (this one was more dramatic at 200 than at 70) and maybe look at out-of-focus lights. I think that should be a pretty sensitive test.

  • Eric Bowles

    Roger – great report!

    Do you have any suggestions for testing filters? It’s easy to buy higher grade filters and use them only when needed, but the risk of cheap knockoffs is something that may require testing. Obviously I don’t have your friend OLAF.

  • Pete Myers

    Hi Roger:
    Let us mention one other aspect in regard to filters; plastic filter threads. I truly think we should all stop buying any lens with a plastic filter thread until the industry reverts back to metal. For those of us that use filters at altitude (deep cut UV) or contrast filters for black and white, the industries move towards all-plastic filter threads has been a disaster.
    Pete

  • Al Majauskas

    Excellent article Roger. What an eye opener. I’ve always used filters, mainly to protect. Now I’m wondering if filters are responsible for back/front-focusing issues or similar out-of-focus issues blamed on poor lens design. I’ve noticed my long lens won’t focus with polarizing filters. Seems now there’s lots of filter problems. Also, how vulnerable are naked lenses without these? Are there simple uncoated glass filters available? Are there filter reviews out there testing for filter acuity? Thanks.

  • Edmond Wong

    Is there a new updated list of some of the newer models other than just the one on lenstip.com from 2007? I recently bought a Hoya Fusion Antistatic Protector. I can’t tell from looking at the Hoya site if this is equivalent to one of their more expensive ones or not. It’s made in japan. I was going to go without a filter but I was planning on doing newborn pictures and they might pee on my lens.

  • Steven Leibson

    Roger, thank you for moving the filter discussion from opinion to cold hard fact. The four OLAF images do more to inform me than years of opinion posts. I’ve been shooting SLRs since 1972 and back then, I always had a UV or Sky 1A filter on my lenses for protection and for the slight boost in IQ they supposedly provided. I continued this practice for a while when I switched to dSLRs but as the resolutions climbed above 8Mpixels, and with your previous posts on filters, I unscrewed them all and put them away. Now I will no longer even look back. Thanks for your posts.

    –Steve

  • Jakub S.

    If I was to shoot a rallycross (i don’t do that) maybe I?l put on a hardened protector filter. Otherwise I think any filter is a bad idea if not needed for some special effect (like polarizing).

  • Chik Sum

    Hi Roger, Any idea if the returned filter being a counterfeit one? since here in HK quite a lot of people have found some cheap fake B+W MRC which makes all lens look like BS

  • Franck Mée

    I tested a low-cost polarizing filter last year. It worked nicely and was trouble-free at 50 mm, but the longer the focal length, the worse it got — and past 200 mm, pictures were absolutely awful and definitely unusable.
    What’s fun is that some reflections looked strangely like OLAF’s pictures using this UV filter. So thanks for the reminder!
    (For the curious ones who read French, I made a mini-report at the time: https://photo.h26.me/2016/05/07/pola-pola-bof/ .)

  • Samuel H

    I don’t use protective filters, but I do use ND filters a lot (I shoot mostly video). I tested them when I bought them and they were fine. But that’s when they were new and clean; I should probably do another round someday…

  • walterunderwood

    Haven’t had filters on my lenses for decades. Lens hoods are the best.

  • Ed Hassell

    I started out with the no-filter crowd. And, for the most part, I’m still there; however, I have B+W XS-Pro slim, nano-multicoated UV Haze filters in sizes for each of my lenses just in case they’re needed. For general use, my lenses go naked. When I’m shooting in potentially foul situations and where there are airborn contaminates, around sand or water spray, the filter goes there first.

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