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6 minutes ago, Harry Harrison said:

Actually how about a surprise pick & mix bag of cheap filters to experiment on, I could come up with that.:)


And/or we could organise collecting filters that have some defect with proven weird optical effects and award them to the winner who could then write a short thesis on the cause based on actual experimental evidence. I can think of few things more exciting to while away the hours of the next lockdown. 

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I am hesitant to use any filters except for maybe a polarizing filter.  I figure I can do most things I need to do in Camera Raw or in Photoshop.  You spend hundreds, if not thousands on a lens and then put a cheap piece of glass on it.  

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17 minutes ago, Michael Ventura said:

I am hesitant to use any filters except for maybe a polarizing filter.  I figure I can do most things I need to do in Camera Raw or in Photoshop.  You spend hundreds, if not thousands on a lens and then put a cheap piece of glass on it.  


It is silly for sure to put a cheap filter on an expensive lens. However,  I always use protective filters albeit only very good quality ones and make sure I keep them clean. I would prefer to replace a filter than a lens and I don’t buy the argument that modern lens glass is so robust that filters are not necessary. I cannot detect any deterioration in image quality from using the filters I use on my lenses and I have done some pretty thorough checking. 

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I am with MDM. I only put good protective filters in all my lenses, just after bought them. And use a polarizing filter with my all-around lens in hikes. 

In my case with the 300mm, I put on the cheap filter that the retailer included because my ordered B+W filter (it cost me almost 70€) hadn't arrived yet...and I wanted to test my new lens badly :)

My deception was at home, checking the images at 100%....ruined most of them. One of them is my avatar image, but at that size you can't find the lines ;) 

At least my experience helped someone else and save some good money for expend in better props.

About the physics involved in that effect, no idea. Actually I think I didn't throw away the cheap filter...I kept it just in case for DIY brico projects. I can offer it for the cheap filters mix bag prize :D

Edited by shearwater
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I have been reading up on this problem for a while now and I have seen reports as early as 2007 of people who have fixed it by omitting the filter. Also good quality filters are being reported as problematic.

Keywords I have used so far: diagonal; banding; bokeh; filter.

No real explanation yet.

Other than: told you not to use filters.

So far only 1 solutions: don't use a filter.

Here's a nice write up about bokeh.

 

wim

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3 hours ago, shearwater said:

I am with MDM. 

 

 

I see we have been to some of the same places. I was in El Hierro in October 2012 and you were there November 2012. You have some great underwater shots in Mar de las Calmas. I stuck to the land myself photographing the volcanoes and the landslides. El Hierro is amazing for the lack of tourism. And northern Spain. You have some great landscapes there. So vast and so many amazing places. I will have to get back there sometime before too long. 

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1 hour ago, wiskerke said:

I have been reading up on this problem for a while now and I have seen reports as early as 2007 of people who have fixed it by omitting the filter. Also good quality filters are being reported as problematic.

Keywords I have used so far: diagonal; banding; bokeh; filter.

No real explanation yet.

Other than: told you not to use filters.

So far only 1 solutions: don't use a filter.

Here's a nice write up about bokeh.

 

wim

 

Fascinating. I have some experience in diffraction and interference effects with lasers, but this effect is puzzling. The interval between the "fringes" is quite small and nominally linear unlike newtons rings caused by interference between the stray refletion and main beam between nominally parallel surfaces. Others who have seen the effect report that rotating the filter rotates the effect by the same amount, perhaps suggesting the origin of the effect lies entirely within the filter (and not interference with a stray reflection of the camera sensor for example). But it also only seems to occur in out of focus areas, which would rely on effects outside the filter... Weird. There's probably a simple explanation, but it escapes me at the moment.

 

Must check my filters on a long lens.

 

Mark

 

Edited by M.Chapman
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Fascinating. I have some experience in diffraction and interference effects with lasers, but this effect is puzzling. The interval between the "fringes" is quite small and nominally linear unlike newtons rings caused by interference between the stray refletion and main beam between nominally parallel surfaces. Others who have seen the effect report that rotating the filter rotates the effect by the same amount, perhaps suggesting the origin of the effect lies entirely within the filter (and not interference with a stray reflection of the camera sensor for example). But it also only seems to occur in out of focus areas, which would rely on effects outside the filter... Weird. There's probably a simple explanation, but it escapes me at the moment.

 

Must check my filters on a long lens.

 

Mark

 

There's even a report from 1999 on film. So it seems no sensor related problem. The effect seems greater at longer lenses and smaller sensors though.

So far no real explanation.

 

wim

Edited by wiskerke
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5 hours ago, MDM said:

 

I see we have been to some of the same places. I was in El Hierro in October 2012 and you were there November 2012. You have some great underwater shots in Mar de las Calmas. I stuck to the land myself photographing the volcanoes and the landslides. El Hierro is amazing for the lack of tourism. And northern Spain. You have some great landscapes there. So vast and so many amazing places. I will have to get back there sometime before too long. 

 

Yes, El Hierro is a great and fascinating island. So wild and rough...sometimes you can feel the isolation like a chill. But, hey, don't say it too loudy...it is a secret place, and should remain like that ;)  I had to choose between underwater and land...and the water for me always win. You have great images from all over the island, do they sell well?

I can see that you have been in La Palma too. Another wonderful and beautiful place: La Isla Bonita. I was there in 2012 too.

I'm from northern Spain...green pastures, rough cold sea, high mountains, rainy and cloudy. More similar to England or Ireland. We are celtic too! Now I live in the mediterranean...so much heat in the summer for me. But the light is so different, so clear. And winters are fabulous.

Sorry to divert the topic...back to lens filters! :)

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1 hour ago, wiskerke said:

There's even a report from 1999 on film.

Fascinating, seems to be the same effect, and if I'm reading him correctly he can actually see them through the viewfinder, and see them disappear when he removes the filter.

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I did buy a protection filter for my 18mm Batis but for most uses, the lens hood offers sufficient protection.  I'll use the protection filter if I'm ever around a beach or active volcano.

 

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11 hours ago, shearwater said:

 

Yes, El Hierro is a great and fascinating island. So wild and rough...sometimes you can feel the isolation like a chill. But, hey, don't say it too loudy...it is a secret place, and should remain like that ;)  I had to choose between underwater and land...and the water for me always win. You have great images from all over the island, do they sell well?

I can see that you have been in La Palma too. Another wonderful and beautiful place: La Isla Bonita. I was there in 2012 too.

I'm from northern Spain...green pastures, rough cold sea, high mountains, rainy and cloudy. More similar to England or Ireland. We are celtic too! Now I live in the mediterranean...so much heat in the summer for me. But the light is so different, so clear. And winters are fabulous.

Sorry to divert the topic...back to lens filters! :)


Yes shhhh El Whero ?  😎. I spent a month there on two separate trips in 2012 and didn’t meet a single native English speaker. It is completely off the radar for typical Canarian tourism. And no I have made very few sales of my pics from there. Not a big deal though as I really enjoyed the experienceI was mainly interested in the geology which doesn’t really sell anyway for me. The reason I went there was the underwater eruption in November 2011 but it had finished by the time I went. It had a big impact on tourism as well apparently which made it even quieter. I love the Canaries. I’ve been around all the islands and each one is unique. And I love northern Spain. It’s been too long now since I’ve been there. The rest of Spain - someday I hope. 

 

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7 hours ago, MizBrown said:

I did buy a protection filter for my 18mm Batis but for most uses, the lens hood offers sufficient protection.  I'll use the protection filter if I'm ever around a beach or active volcano.

 


Depending on the volcano and the type of activity, you might need more than a protective lens filter. 

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12 hours ago, Sally R said:

Really glad the problem is solved Gen!

 

This is an interesting thread for me to read as I have had some similar effects appear in some (but not all) images taken with my Sigma 150-500mm lens. I have always used a filter with this lens and it is also a Kenko, so interesting to here MDM's comments about some Kenko filters. At the time I remember it not being cheap and thinking I was buying a decent filter, but it could well be that the filter is the culprit. I always thought it was some kind of user error on my part, that there was something not quite working possibly in relation to the angle I was holding the lens at in combination with my choice of aperture that might be affecting some of the images.

 

I'm also using my Sigma lens with a crop sensor Nikon D5200, so this may also fit with the possibility Wim mentions above of smaller sensor sizes combined with a telephoto lens being possible factors as well.

 

In the next few days I'll try some sample shots to first try and replicate the effect, then taken another without the filter and compare. I often use the lens hood so this may protect the lens if I decide to go without a filter from now on.

 

Interesting case. Maybe you could test with and without the filter at a couple of focus lengths and different f stops. At least at the extremes.

Then check if you can see it in the viewfinder/live screen. If that's the case maybe test a couple of filters (could be used of course) at a shop or some other outlet and see if there are any that give a perfect image. (= as if there's no filter.)

 

I have no idea how it will show on a Siemens star, but I'm pretty sure it will be visible.

Good Siemens stars here.

I would print 3 and tape them each to a stick and put them in the scene you normally use. One at the point you normally focus on and two further away. Mark the distances so you can repeat it somewhere else like outside a shop.

 

wim

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One of the many reasons I do not use filters on any of my glass.  I do have really strong hoods on all lenses.  I've also 

had many lenses for over 20 years and not a mark on any front elements.

 

Chuck

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20 minutes ago, Chuck Nacke said:

One of the many reasons I do not use filters on any of my glass.  I do have really strong hoods on all lenses.  I've also 

had many lenses for over 20 years and not a mark on any front elements.

 

Chuck

 

I wish I could say the same. Quite early on I needed an expensive new front lens for my 1.2-55 Zuiko. (The one that makes the Geiger counter go tick-tick-tick.) Luckily I had a good insurance. Which however became more expensive over the years with small or larger mishaps. So I started using filters on almost all my lenses and had to change those at least every two years for the 24mm and 100mm which were always on my cameras. And the old filters always had scratches and nicks.

And not because of using Brillo. Plus I always used rubber lens hoods on most and plastic Leica style ones on the wide angles - I went through a few.

While shooting I never used lens caps though. Only after wrapping up.

 

I have since long been converted from the always on - unless  to the no filter - unless camp. Besides some of my lenses wouldn't take filters. Like my 17mm which has it's lens cap tied to it with a string. And which I have babied always. But after 10-12 years there are marks on that lens.

 

Maybe it's age (mine): there have certainly been times that I was much less careful and certainly not shy. When lens or camera sometimes came into contact with hard surfaces or teeth even (not mine). 😁

 

wim

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1 hour ago, wiskerke said:

 

I wish I could say the same. Quite early on I needed an expensive new front lens for my 1.2-55 Zuiko. (The one that makes the Geiger counter go tick-tick-tick.) Luckily I had a good insurance. Which however became more expensive over the years with small or larger mishaps. So I started using filters on almost all my lenses and had to change those at least every two years for the 24mm and 100mm which were always on my cameras. And the old filters always had scratches and nicks.

And not because of using Brillo. Plus I always used rubber lens hoods on most and plastic Leica style ones on the wide angles - I went through a few.

While shooting I never used lens caps though. Only after wrapping up.

 

I have since long been converted from the always on - unless  to the no filter - unless camp. Besides some of my lenses wouldn't take filters. Like my 17mm which has it's lens cap tied to it with a string. And which I have babied always. But after 10-12 years there are marks on that lens.

 

Maybe it's age (mine): there have certainly been times that I was much less careful and certainly not shy. When lens or camera sometimes came into contact with hard surfaces or teeth even (not mine). 😁

 

wim

Wim,

 

By "Strong" I meant METAL.  Through the years I smashed a lot of metal hoods, but never a front element. Those lenses were used in combat zones, riots and skiing in the Caucasus Mountains (Elbrus)

 

Chuck

Edited by Chuck Nacke
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I also use hoods on all my lenses in lieu of a protective filter.  Once in a while they do stop lens flare but I use them more to protect the front element.  Nowadays, metal hoods are a rarity but the plastic ones have worked well and are cheap and easy to replace.

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10 minutes ago, Sally R said:

Just a quick update to the above. I can confirm that the banding disappears without the filter. Yay!

Good of you to post one of your own images with this problem, and to confirm that in your case it was the filter. I'd not been aware of this problem before this thread and I don't use long lenses but I'm fascinated to know the cause. Trouble is, as Wim has suggested, nobody seems to know, searching for 'diagonal streaking bokeh' reveals a host of examples in various threads across all brands of lenses and it doesn't seem to just be caused by cheap filters as has already been said.

 

Now most manufacturers will actually recommend that you use their own high quality branded filters on their lenses so surely their lens designers would know of this problem and what would be causing it? Do they even recommend not using a filter on certain long lenses I wonder?

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10 hours ago, Michael Ventura said:

I also use hoods on all my lenses in lieu of a protective filter.  Once in a while they do stop lens flare but I use them more to protect the front element.  Nowadays, metal hoods are a rarity but the plastic ones have worked well and are cheap and easy to replace.


Hoods can help to prevent damage due to knocks but do nothing against abrasives (e.g. sand) or corrosives (e.g. salty sea spray). Even if there are no visible scratches, the effects on the lens coatings are likely unknown. I have numerous high quality filters that get scratched over time and zi replace them. Put it this way. If I was buying a used lens from the owner and they said they never used protective filters, then I wouldn’t buy it. 

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Marianne Oelund, who is/was one of resident lens gurus of the Dpreview Nikon forum said this about it:

 

It's called doubling and it's normal.

Unless the lens is intentionally designed with some under-correction of SA (spherical aberration), high-contrast lines in backgrounds will provoke this kind of detail.  It is because the edges of the blur circles are abrupt, instead of diffuse.

It is difficult to maintain a pleasing background blur across the focal range of zoom lenses, and this aspect of design usually has a low priority for telephoto zooms.

 

And in a different post she explained the term for it:

It's "nisen bokeh." In Japanese, "ni" = two; "sen" = line. Double-line bokeh.  No capitalization needed.

 

Except of course it isn't normal if it disappears when the filter is removed. Or the pattern changes direction if the filter is rotated.

So the filter is causing it or exaggerating it in certain cases.

My theory at the moment is that the filter interferes with the solution the lens designers have come up with to reduce that normal nisen bokeh.

Now why? And is it just a certain sort of filter? We assume it's because it's a bad filter. But what if it is because it's a good filter?

 

First of all, putting a piece of glass or a lens in the optical path does alter the focus point slightly. So that could be it. Just a simple focus problem.

It could be that UV light has something to do with it. A bit like CA, but now with UV in stead of blue and red. Again basically a focus problem.

Both documented problems. However those two still do not explain the directional thing and that it changes with rotation.

 

I should read up on what a UV filter actually does and how it's achieved in the various types. What makes a UV filter cheap and what makes it expensive?

 

So here are some of the resources I have been reading/revisiting in the course of this:

 

Paul van Walree:

https://web.archive.org/web/20070823003700/http://www.vanwalree.com/optics/bokeh.html

https://web.archive.org/web/20120118221937/http://toothwalker.org/optics/spherical.html

 

Klaus Shuler:

http://www.bokehtests.com/styled/index.html

He thinks/explains it's caused by IS/VR: http://www.bokehtests.com/page2/index.html

So like always when a problem is difficult to understand or explain, there may be different things that cause it. Maybe even at the same time.

 

Dave Etchells: it's aspheric lenses.

 

Roger Cicala: one of many good articles: https://www.lensrentals.com/blog/2010/10/the-seven-deadly-aberrations/

And on using or not using protective filters: https://www.lensrentals.com/blog/2016/12/front-element-lens-protection-revisited/

And here again on filters with some images that show the problem with cheap filters https://www.lensrentals.com/blog/2017/05/yet-another-post-about-my-issues-with-uv-filters/

Which seems to answer my question if it could be that a good filter is causing the problems. At least it shows a bad filter causing problems that may lead to the dreaded nisen bokeh.

 

wim

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28 minutes ago, wiskerke said:

Marianne Oelund, who is/was one of resident lens gurus of the Dpreview Nikon forum said this about it:

 

It's called doubling and it's normal.


 

 

Klaus Shuler:

http://www.bokehtests.com/styled/index.html

He thinks/explains it's caused by IS/VR: http://www.bokehtests.com/page2/index.html

So like always when a problem is difficult to understand or explain, there may be different things that cause it. Maybe even at the same time.

 

 

Roger Cicala: one of many good articles: https://www.lensrentals.com/blog/2010/10/the-seven-deadly-aberrations/

And on using or not using protective filters: https://www.lensrentals.com/blog/2016/12/front-element-lens-protection-revisited/

And here again on filters with some images that show the problem with cheap filters https://www.lensrentals.com/blog/2017/05/yet-another-post-about-my-issues-with-uv-filters/

Which seems to answer my question if it could be that a good filter is causing the problems. At least it shows a bad filter causing problems that may lead to the dreaded nisen bokeh.

 

wim

 

Thanks for all that win. I haven’t read all yet. The Lens Rentals articles are great and written by someone who clearly knows what he is talking about. The idea that the lens cap itself can cause damage to the front element or filter coating, particularly in larger filter sizes, is very interesting. I reckon I have had that happen once or twice  
 

The IS/VR theory can be immediately binned as a single cause in itself as Shearwater has clearly demonstrated that the effect happens on non-VR lenses and disappeared when the first filter was removed. 

 

 

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3 minutes ago, MDM said:

 

Thanks for all that win. I haven’t read all yet. The Lens Rentals articles are great and written by someone who clearly knows what he is talking about. The idea that the lens cap itself can cause damage to the front element or filter coating, particularly in larger filter sizes, is very interesting. I reckon I have had that happen once or twice  
 

The IS/VR theory can be immediately binned as a single cause in itself as Shearwater has clearly demonstrated that the effect happens on non-VR lenses. 

 

 

 

Not so fast, IS/VR may cause some of it as well.

 

It occurred to me that a particular problem with the filters causing circular marks on the front lens (and I assume on the back of the filter as well) is that these are large diameter filters. Which may be made for wide angle lenses, and usually sold as slim filters. Some of these come (at least used to come) with a caveat: be careful that your front lenses don't protrude too much.

 

wim

 

 

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