I've about had it with Nikon's VR

michaeladawson · Apr 19, 2024

Bob A L said:
How far in front of the squirrel was that weed or whatever it is?

No clue about that. I never saw it. But knowing my yard it was a small, winter dried stem in our garden plots that was probably a couple feet in front of the squirrel.

Bob A L said:
And a curiosity on my part, does this always appear in only processed RAW shots, or does it happen in jpegs sooc also?

Wouldn't know that either. I never shoot jpeg. But to be clear, what do you mean about processed raw shots? I certainly understand that raw files are "processed" as soon as you load them into a raw converter. But all of this ugly bokeh that we are talking about happens without any further raw processing. I can guarantee you that it would show up in jpeg files sooc as well if you have the right lenses in the right setting.

ghostfox_1 · Apr 19, 2024

Bob A L said:
How far in front of the squirrel was that weed or whatever it is? And a curiosity on my part, does this always appear in only processed RAW shots, or does it happen in jpegs sooc also?

It'd appear in both. It's a property of something being in front of the lens (in this case) at a specific distance to the subject.

SKersting66 · Apr 19, 2024

michaeladawson said:
ARClark said:

I like the nisen bokeh idea as opposed to VR/IBIS issues. However, I also feel like my 800 PF may be rendering busier backgrounds than my 500E FL with and without TCs; but I really need to do a side by side comparison before stating that definitively.

Click to expand...

I do too. But do keep in mind that one of the opinions I came across in my reading did say that VR can occasionally make the issue worse. Because VR changes the alignment of the lens elements it can move the responsible lens elements to the extremes, making the issue worse. However, there is some opinion that Nikon re-centers the lens elements before taking the shot, lessening any VR contribution. IBIS probably plays no role in this as it is simply moving the sensor around and not the lens elements.

Only the normal VR mode recenters; that's what causes the large viewfinder jump. Sport mode does not, and therefore gives a smoother viewfinder experience.

Lance B · Apr 19, 2024

michaeladawson said:
A couple of responders mentioned nisen bokeh, a term I had not heard before. I've done just a little searching on this and it seems that this may indeed be what I am seeing in many of my telephoto shots.

I'll mangle this short summary, but it seems like this is caused by spherical aberrations in highly corrected lenses. Telephotos seem to be more subject to it. Today's highly corrected lenses use a number of different lens elements (aspherical elements, different refractive indices, etc) to correct various image distortions.

It happens with very thin objects (blades of grass, twigs, etc) just out of the DOF zone in front of and behind the plane of focus, but the depth of the area is greater behind the subject than in front.

The effect is a product of current lens designs, I guess. It can be present in a perfectly aligned lens but is exacerbated by a lens where the corrective elements are de-centered. We have very sharp and lightweight telephoto lenses today. But one of the trade-offs is more pronounced nisen bokeh.

The effect is not necessarily caused by VR/OIS. However, VR can exacerbate the problem. VR works by moving different elements around inside the lens. An intentional de-centering of elements, if you will. When lenses are moved towards the extreme of their travel for VR correction the aberrations will be greatest. This would explain what someone here mentioned, that Nikon re-centers the image just before the photo taken. This would help minimize the effect.

Because the effect is exacerbated by the alignment of lens elements I would take that to mean that IBIS would play no role in nisen bokeh effects.

So as I said, I probably mangled that explanation and made some misstatements. But I think I have a general idea of what is going on.

In a few bullet points...

It seems the effect I'm seeing is likely nisen bokeh

Nisen bokeh is has become more prevalent in telephoto lenses due to the highly corrective nature of current telephoto lens designs (aspherical elements, etc.)

The effect is not directly caused by VR/OIS, but can be exacerbated by it as lens elements are moved further out of alignment to keep the subject sharp (remove vibration).

Dinosaur dave · Apr 19, 2024

michaeladawson said:
A couple of responders mentioned nisen bokeh, a term I had not heard before. I've done just a little searching on this and it seems that this may indeed be what I am seeing in many of my telephoto shots.

I'll mangle this short summary, but it seems like this is caused by spherical aberrations in highly corrected lenses. Telephotos seem to be more subject to it. Today's highly corrected lenses use a number of different lens elements (aspherical elements, different refractive indices, etc) to correct various image distortions.

It happens with very thin objects (blades of grass, twigs, etc) just out of the DOF zone in front of and behind the plane of focus, but the depth of the area is greater behind the subject than in front.

yes!

michaeladawson said:
The effect is a product of current lens designs, I guess. It can be present in a perfectly aligned lens but is exacerbated by a lens where the corrective elements are de-centered. We have very sharp and lightweight telephoto lenses today. But one of the trade-offs is more pronounced nisen bokeh.

I'm not so sure it's to do with modern lens designs actually ....

.... my first experience with it was with the Sigma 50-500mm F4-6.3 EX lens ..... no VR there, a dated lens ...... after that came the AF-S 500mm F4D no VR (another old lens) and of course no IBIS in the cameras; D7100 + D750 .... the nisen bokeh was strong, OOF stalks of grass became split with brightly lit edges (highlighted) , the center of the stalk being darker and almost invisible ..... when you have multiple stalks, you have multiple multiple splitting and all those splits interfere with one another cause interference artifacts ...

My most modern lens is the AF-S 600mm F4E FL VR ..... after hearing all the hullabaloo about it's wonderful bokeh I was somewhat disappointed to find nisen bokeh very similar to most other telephoto lenses I tried .....

michaeladawson said:
The effect is not necessarily caused by VR/OIS. However, VR can exacerbate the problem. VR works by moving different elements around inside the lens. An intentional de-centering of elements, if you will. When lenses are moved towards the extreme of their travel for VR correction the aberrations will be greatest. This would explain what someone here mentioned, that Nikon re-centers the image just before the photo taken. This would help minimize the effect.

Indeed this would be worth testing for in controlled images .....

michaeladawson said:
Because the effect is exacerbated by the alignment of lens elements I would take that to mean that IBIS would play no role in nisen bokeh effects.

So as I said, I probably mangled that explanation and made some misstatements. But I think I have a general idea of what is going on.

In a few bullet points...

It seems the effect I'm seeing is likely nisen bokeh ....

Yes!

michaeladawson said:
Nisen bokeh is has become more prevalent in telephoto lenses due to the highly corrective nature of current telephoto lens designs (aspherical elements,

The effect is not directly caused by VR/OIS, but can be exacerbated by it as lens elements are moved further out of alignment to keep the subject sharp (remove vibration).

Advancing further:

...... take a look at the lens review site Opticallimits: ( a great lens site btw) here's a link to the Sigma 150mm F2.8 non OS macro lens ..... looking at the card/statue/sparkly scene, it has almost the perfect bokeh, minimal highlighting and no nisen splitting with clean smooth backgrounds ......when you look at the bokeh fringing section it can be clearly seen that behind the plane of focus the numbers are soft and smooth whereas in front there are clear signs of splitting in front ... hence the review states rougher bokeh in front of TPoF.

I picked that lens example because I own it and love it's gentle rendering in the focusing transitions, which often trip up lesser glass, background bokeh is as good as any lens I own ......... it's quite rare beast actually.

https://photozone.de/nikon_ff/624-sigma15028ff?start=1

Lastly, IMHO the time has come that lens manufacturers to start addressing this issue, it's been around for years now and much as telephoto lenses have improved out of all proportion, nisen bokeh has for the most part remained similar in the focus transition zones.

FrankG · Apr 20, 2024

michaeladawson said:
A couple of responders mentioned nisen bokeh, a term I had not heard before. I've done just a little searching on this and it seems that this may indeed be what I am seeing in many of my telephoto shots.

I'll mangle this short summary, but it seems like this is caused by spherical aberrations in highly corrected lenses. Telephotos seem to be more subject to it. Today's highly corrected lenses use a number of different lens elements (aspherical elements, different refractive indices, etc) to correct various image distortions.

Not at all sure whether Telephotos are more subject to it. It has been reported for all sorts of lenses including wide-angles from various manufacturers. For example see tis old thread:

Eased up on the hammer.... ol' nisen bokeh issue. - FM Forums (fredmiranda.com)

michaeladawson said:
It happens with very thin objects (blades of grass, twigs, etc) just out of the DOF zone in front of and behind the plane of focus, but the depth of the area is greater behind the subject than in front.

The effect is a product of current lens designs, I guess. It can be present in a perfectly aligned lens but is exacerbated by a lens where the corrective elements are de-centered. We have very sharp and lightweight telephoto lenses today. But one of the trade-offs is more pronounced nisen bokeh.

The effect is not necessarily caused by VR/OIS. However, VR can exacerbate the problem. VR works by moving different elements around inside the lens. An intentional de-centering of elements, if you will. When lenses are moved towards the extreme of their travel for VR correction the aberrations will be greatest. This would explain what someone here mentioned, that Nikon re-centers the image just before the photo taken. This would help minimize the effect.

Because the effect is exacerbated by the alignment of lens elements I would take that to mean that IBIS would play no role in nisen bokeh effects.

So as I said, I probably mangled that explanation and made some misstatements. But I think I have a general idea of what is going on.

In a few bullet points...

It seems the effect I'm seeing is likely nisen bokeh

Nisen bokeh is has become more prevalent in telephoto lenses due to the highly corrective nature of current telephoto lens designs (aspherical elements, etc.)

The effect is not directly caused by VR/OIS, but can be exacerbated by it as lens elements are moved further out of alignment to keep the subject sharp (remove vibration).

I have seen similar effects occasionally with some of my bird shots where OOF twigs or branches can arbitrarily sometimes show bits of this sort of effect although usually much more muted and less noticeable than in your example - but it can occur. I have seen the effect occasionally with other lenses also. Can also tend to get enhanced or exagerrated a bit I think by certain kinds of processing enhancements (sharpening, applying excessive added "microcontrast" etc).

So I wonder how well (or not) the latest "exotic" telephotos (ie 400mm f/2.8 TC, 600mm f/4 TC) from Nikon manage to deal with this issue. Is it really, as supposed, simply due to the "highly corrective" nature of current lens designs? Or perhaps it could be that the corrections are imperfect? I haven't heard or seen of any reports of this being at all troublesome with those top-end exotics which I would think are probably the most highly corrected of all !? There again I haven't had a chance to use either of the current top-end tele Nikkors but I have seen quite a few samples of photos from the 400mm f/2.8 TC suggesting the most excellent bokeh characteristics as well as great sharpness.

Frank

chambeshi · Apr 20, 2024

Thanks for an educational thread. Here's an overview by Dave Etchels about bokeh and precision optical manufacturing). This is one of his well researched articles archived in the late IR

The end of onion-ring bokeh? Panasonic beats the curse of aspheric lenses - Imaging Resource

No free lunch? Aspheric lenses meant onion-ring bokeh... until now. Aspheric lens technology is part of the reason many modern photographic lenses are better in so many respects to models from 50 years ago. Lenses…

www.imaging-resource.com

"As photographers have become more sophisticated and learned from each other over the Internet though, more and more people have come to appreciate the blessings of beautiful bokeh."

michaeladawson said:
A couple of responders mentioned nisen bokeh, a term I had not heard before. I've done just a little searching on this and it seems that this may indeed be what I am seeing in many of my telephoto shots.

I'll mangle this short summary, but it seems like this is caused by spherical aberrations in highly corrected lenses. Telephotos seem to be more subject to it. Today's highly corrected lenses use a number of different lens elements (aspherical elements, different refractive indices, etc) to correct various image distortions.

It happens with very thin objects (blades of grass, twigs, etc) just out of the DOF zone in front of and behind the plane of focus, but the depth of the area is greater behind the subject than in front.

The effect is a product of current lens designs, I guess. It can be present in a perfectly aligned lens but is exacerbated by a lens where the corrective elements are de-centered. We have very sharp and lightweight telephoto lenses today. But one of the trade-offs is more pronounced nisen bokeh.

The effect is not necessarily caused by VR/OIS. However, VR can exacerbate the problem. VR works by moving different elements around inside the lens. An intentional de-centering of elements, if you will. When lenses are moved towards the extreme of their travel for VR correction the aberrations will be greatest. This would explain what someone here mentioned, that Nikon re-centers the image just before the photo taken. This would help minimize the effect.

Because the effect is exacerbated by the alignment of lens elements I would take that to mean that IBIS would play no role in nisen bokeh effects.

So as I said, I probably mangled that explanation and made some misstatements. But I think I have a general idea of what is going on.

In a few bullet points...

It seems the effect I'm seeing is likely nisen bokeh

Nisen bokeh is has become more prevalent in telephoto lenses due to the highly corrective nature of current telephoto lens designs (aspherical elements, etc.)

The effect is not directly caused by VR/OIS, but can be exacerbated by it as lens elements are moved further out of alignment to keep the subject sharp (remove vibration).

barkleytom · Apr 20, 2024

I am with you here. This has been a common occurence for many years and nothings was done about it!

Mako2011 · Apr 20, 2024

barkleytom said:
I am with you here. This has been a common occurence for many years and nothings was done about it!

The manufacture can't because the issue shown here has nothing to do with VR. The issue is related to nisen bokeh which is more an inherent lens/atmospheric/scene dynamics issue rather than a VR one. Happens with or without stabilization and not limited to Nikon

michaeladawson · Apr 20, 2024

FrankG said:
I have seen similar effects occasionally with some of my bird shots where OOF twigs or branches can arbitrarily sometimes show bits of this sort of effect although usually much more muted and less noticeable than in your example - but it can occur. I have seen the effect occasionally with other lenses also. Can also tend to get enhanced or exagerrated a bit I think by certain kinds of processing enhancements (sharpening, applying excessive added "microcontrast" etc).

So I wonder how well (or not) the latest "exotic" telephotos (ie 400mm f/2.8 TC, 600mm f/4 TC) from Nikon manage to deal with this issue. Is it really, as supposed, simply due to the "highly corrective" nature of current lens designs? Or perhaps it could be that the corrections are imperfect? I haven't heard or seen of any reports of this being at all troublesome with those top-end exotics which I would think are probably the most highly corrected of all !? There again I haven't had a chance to use either of the current top-end tele Nikkors but I have seen quite a few samples of photos from the 400mm f/2.8 TC suggesting the most excellent bokeh characteristics as well as great sharpness.

Frank

Perhaps I should have worded it slightly differently. Maybe an alternate phrasing could have been "highly corrective optics imperfectly done." Meaning that the types of lens elements used today for correction do a great job in most cases. But they need to be done perfectly in order to avoid exacerbating side effect distortions such as nisen bokeh. So you get wonderfully sharp images out of todays mid-range priced telephotos at the expense of things like potentially ugly nisen bokeh. You pay a lot more for the highest quality lenses that go a few steps further.

michaeladawson · Apr 20, 2024

chambeshi said:
Thanks for an educational thread. Here's an overview by Dave Etchels about bokeh and precision optical manufacturing). This is one of his well researched articles archived in the late IR

https://www.imaging-resource.com/ne...-panasonic-beats-the-curse-of-aspheric-lenses

"As photographers have become more sophisticated and learned from each other over the Internet though, more and more people have come to appreciate the blessings of beautiful bokeh."

Thank you. A very interesting read.

They mention nisen bokeh in the article, but the article is mainly about the cause and remediation of onion-ring bokeh. Is the linear form of ugly bokeh that is talked about in this DPR thread I started for the most part simply onion ring bokeh on a linear axis?

wcan · Apr 20, 2024

I would think if the subject is tack sharp, than the VR is doing it's job, end of story. If there is some type artifact in the OOF areas, what could the VR system do differently?...its job is to keep the subject "in one place" on the sensor.

SKersting66 · Apr 20, 2024

michaeladawson said:
chambeshi said:

Thanks for an educational thread. Here's an overview by Dave Etchels about bokeh and precision optical manufacturing). This is one of his well researched articles archived in the late IR

https://www.imaging-resource.com/ne...-panasonic-beats-the-curse-of-aspheric-lenses

"As photographers have become more sophisticated and learned from each other over the Internet though, more and more people have come to appreciate the blessings of beautiful bokeh."

Click to expand...

Thank you. A very interesting read.

They mention nisen bokeh in the article, but the article is mainly about the cause and remediation of onion-ring bokeh. Is the linear form of ugly bokeh that is talked about in this DPR thread I started for the most part simply onion ring bokeh on a linear axis?

"Onion ring" and nisen bokeh are two very different things... I would classify onion ring as being closely related to the PF lens rings that can occur in the bokeh. They are both due to the surface characteristics of lens elements.

Nisen bokeh is due to correction of spherical aberrations. This shows an overcorrected lens and why it renders "soap bubble" bokeh in the BG.

uncorrected/undercorrected SA would render the bokeh opposite in the FG/BG

Now envision the BG blur is not due to a round detail, but rather more elliptical, then imagine it is linear by cutting off the top/bottom; and you can see how we get nisen bokeh.

soap bubble bokeh becomes nisen bokeh for linear blur; for an un/undercorrected lens it would occur in the FG

--

Steven Kersting

Explore Steven Kersting’s 751 photos on Flickr!

www.flickr.com

Roy Kikuta · Apr 20, 2024

SKersting66 said:
michaeladawson said:

chambeshi said:

Thanks for an educational thread. Here's an overview by Dave Etchels about bokeh and precision optical manufacturing). This is one of his well researched articles archived in the late IR

https://www.imaging-resource.com/ne...-panasonic-beats-the-curse-of-aspheric-lenses

"As photographers have become more sophisticated and learned from each other over the Internet though, more and more people have come to appreciate the blessings of beautiful bokeh."

Click to expand...

Thank you. A very interesting read.

They mention nisen bokeh in the article, but the article is mainly about the cause and remediation of onion-ring bokeh. Is the linear form of ugly bokeh that is talked about in this DPR thread I started for the most part simply onion ring bokeh on a linear axis?

Click to expand...

"Onion ring" and nisen bokeh are two very different things... I would classify onion ring as being closely related to the PF lens rings that can occur in the bokeh. They are both due to the surface characteristics of lens elements.
Nisen bokeh is due to correction of spherical aberrations. This shows an overcorrected lens and why it renders "soap bubble" bokeh in the BG.

uncorrected/undercorrected SA would render the bokeh opposite in the FG/BG

Now envision the BG blur is not due to a round detail, but rather more elliptical, then imagine it is linear by cutting off the top/bottom; and you can see how we get nisen bokeh.

soap bubble bokeh becomes nisen bokeh for linear blur; for an un/undercorrected lens it would occur in the FG

I’m a bit confused…you make a case for clear distinction between onion ring and nisen bokeh artifacts… but your final argument kind of blurs that line of separation, again. So this begs the question - are PF lenses more prone to producing not only onion ring artifacts, but nisen type bokeh as well - or is the right take-away that all highly corrected lens designs using the micro-stepped concentric ring manufacturing process to produce complex lens elements (such as aspherics) the actual cause of nisen bokeh - noting that the Panasonic manufacturing process for producing aspheric lenses (referenced in an earlier post) looks to me as similar to the way PF elements are made - i.e., concentric rings at a microscopic level? (Apologies in advance - I feel as if I’m arguing with myself in a circular manner - not thinking clearly at this time in the morning before enough cups of coffee!)
Lastly, is anyone prepared to conclude that Nikon’s VR does not cause/contribute to nisen bokeh?

michaeladawson · Apr 20, 2024

SKersting66 said:
SKersting66 said:

Thank you. A very interesting read.

They mention nisen bokeh in the article, but the article is mainly about the cause and remediation of onion-ring bokeh. Is the linear form of ugly bokeh that is talked about in this DPR thread I started for the most part simply onion ring bokeh on a linear axis?

Click to expand...

You say onion ring and nisen bokeh are two very different things. Yet you then go on to say that nisen bokeh is due to correction of spherical aberrations. That is exactly what the article was saying is the cause of onion ring bokeh.

Maybe I was unclear in what I said. I realize that onion ring bokeh is seen in circular out of focus areas. But it sounds like you are basically agreeing with my question. Nisen bokeh is caused by the same thing that causes onion ring bokeh. One displays itself in circular OOF areas, the other in linear OOF objects.

SKersting66 said:
"Onion ring" and nisen bokeh are two very different things... I would classify onion ring as being closely related to the PF lens rings that can occur in the bokeh. They are both due to the surface characteristics of lens elements.
Nisen bokeh is due to correction of spherical aberrations. This shows an overcorrected lens and why it renders "soap bubble" bokeh in the BG.

uncorrected/undercorrected SA would render the bokeh opposite in the FG/BG

Now envision the BG blur is not due to a round detail, but rather more elliptical, then imagine it is linear by cutting off the top/bottom; and you can see how we get nisen bokeh.

soap bubble bokeh becomes nisen bokeh for linear blur; for an un/undercorrected lens it would occur in the FG

--
Mike Dawson

michaeladawson · Apr 20, 2024

Roy Kikuta said:
I’m a bit confused…you make a case for clear distinction between onion ring and nisen bokeh artifacts… but your final argument kind of blurs that line of separation, again. So this begs the question - are PF lenses more prone to producing not only onion ring artifacts, but nisen type bokeh as well - or is the right take-away that all highly corrected lens designs using the micro-stepped concentric ring manufacturing process to produce complex lens elements (such as aspherics) the actual cause of nisen bokeh - noting that the Panasonic manufacturing process for producing aspheric lenses (referenced in an earlier post) looks to me as similar to the way PF elements are made - i.e., concentric rings at a microscopic level? (Apologies in advance - I feel as if I’m arguing with myself in a circular manner - not thinking clearly at this time in the morning before enough cups of coffee!)
Lastly, is anyone prepared to conclude that Nikon’s VR does not cause/contribute to nisen bokeh?

I still am a beginner with respect to these various types of distortions and aberrations.

Nonetheless, I've read enough to conclude that VR is not the cause of nisen bokeh. At the same time, from what I've read, I'm not sure that a poor VR implementation wouldn't contribute to the magnitude of the observed nisen bokeh if it already existed.

Note that I said "poor implementation". After starting this thread I have to say that I don't really believe Nikon has a poor VR implementation after all. So, my original post was a bit off base in it's accusation of Nikon. Nevertheless, I think this thread has been very useful in leading to an understanding the nature and causes of this ugly bokeh effect. At least for me, and I hope others.

Roy Kikuta · Apr 20, 2024

michaeladawson said:
Roy Kikuta said:

I’m a bit confused…you make a case for clear distinction between onion ring and nisen bokeh artifacts… but your final argument kind of blurs that line of separation, again. So this begs the question - are PF lenses more prone to producing not only onion ring artifacts, but nisen type bokeh as well - or is the right take-away that all highly corrected lens designs using the micro-stepped concentric ring manufacturing process to produce complex lens elements (such as aspherics) the actual cause of nisen bokeh - noting that the Panasonic manufacturing process for producing aspheric lenses (referenced in an earlier post) looks to me as similar to the way PF elements are made - i.e., concentric rings at a microscopic level? (Apologies in advance - I feel as if I’m arguing with myself in a circular manner - not thinking clearly at this time in the morning before enough cups of coffee!)
Lastly, is anyone prepared to conclude that Nikon’s VR does not cause/contribute to nisen bokeh?

Click to expand...

I still am a beginner with respect to these various types of distortions and aberrations.

Nonetheless, I've read enough to conclude that VR is not the cause of nisen bokeh. At the same time, from what I've read, I'm not sure that a poor VR implementation wouldn't contribute to the magnitude of the observed nisen bokeh if it already existed.

Note that I said "poor implementation". After starting this thread I have to say that I don't really believe Nikon has a poor VR implementation after all. So, my original post was a bit off base in it's accusation of Nikon. Nevertheless, I think this thread has been very useful in leading to an understanding the nature and causes of this ugly bokeh effect. At least for me, and I hope others.

I hadn’t realized that this very subject had been discussed in so many forums for so long - it was eyebrow raising time for me. Thank you very much, Mike, for your post - I’ve learned a few useful things along the way,

Leonard Shepherd · Apr 20, 2024

Leonard Shepherd said:
If the background looks OK through the viewfinder I do not get your problem.

Redpoll - with VR - obtaining an OK background

:-( :-O :-|

I travelled 80 miles 3 times to get the first image above.

Redpolls are supposed to be rare.

Then one pops up on the back garden feeder :-O

I need about a 2000mm lens and maybe flash to get anywhere near enough sharpness for a good image.

From about 10% of the image area - in fading light - through glass.

It will do as a record of an event - but otherwise like many wildlife shots - maybe disregard theories - and keep trying until you get a good result.

--
Leonard Shepherd
In lots of ways good photography is similar to learning to play a piano - it takes practice to develop skill in either activity.

SKersting66 · Apr 20, 2024

michaeladawson said:
SKersting66 said:

michaeladawson said:

Thank you. A very interesting read.

They mention nisen bokeh in the article, but the article is mainly about the cause and remediation of onion-ring bokeh. Is the linear form of ugly bokeh that is talked about in this DPR thread I started for the most part simply onion ring bokeh on a linear axis?

Click to expand...

Click to expand...

You say onion ring and nisen bokeh are two very different things. Yet you then go on to say that nisen bokeh is due to correction of spherical aberrations. That is exactly what the article was saying is the cause of onion ring bokeh.

Onion ring bokeh (and PF rings) is the concentric circles within and across the entirety of the bokeh; it is showing the surface of the lens element. Onion ring is not the hard outline ("soap bubble") or diffused edge characteristic. It is something of a mistake to say that onion ring is due to it being an aspherical lens element; it is due to how the lens is made (casting); not the resulting surface curvature/refraction.

Nisen (soap bubble), and diffused bokeh are characteristics of spherical aberration and it's correction. Spherical aberration is where the outer rays are bent harder, and they originate from a greater distance, so they converge short of where more central/more parallel rays converge; when not corrected for.

So it is not really correct to say that nisen bokeh is a characteristic of correcting for spherical aberrations either. It is a characteristic of overcorrection of spherical aberration when it occurs in the BG bokeh (which is far more common than FG bokeh).

--
https://www.flickr.com/skersting

michaeladawson · Apr 20, 2024

OK... I think I understand. A subtle but important distinction. Let me see if I understand what you're saying.

Aspherical lens elements are used to correct distortions and aberrations in a lens. Their use cuts down on the number of lens elements to be used in a design. In addition to reducing the element count, another benefit of this is making lighter weight lenses.

So... nisen bokeh vs. onion ring bokeh.

Nisen bokeh can be seen in lenses that have over or under correction using these aspherical lens elements. Whether the effect is seen more in the background or more in the foreground is determined by over or under correction. Does that mean that a lens with perfectly corrected use of aspherical elements would not exhibit nisen bokeh? Or just far less frequently?

Onion ring bokeh on the other hand is a product of the manufacture of these same aspherical elements. Aspherical elements are complicated to make and can be made cheaper and in higher quantities today due to the use of molded lenses (rather than ground). But the process of making the molds results in small concentric rings that are then transferred onto the molded lens.

Is that a reasonable summary of what you are saying?

Would it be reasonable to infer that nisen bokeh would be much less prevalent if aspherical lens elements were not used? I suppose theside effect of this would be less/imperfect correction of other types of distortions and aberrations. And lenses would be bigger and heavier. And perhaps quite a bit more expensive as a result.

I've about had it with Nikon's VR

Forum Pro

Senior Member

Senior Member

Forum Pro

Well-known member

Senior Member

Senior Member

Well-known member

Community Leader

Forum Pro

Forum Pro

Forum Enthusiast

Senior Member

Senior Member

Forum Pro

Forum Pro

Senior Member

Forum Pro

Senior Member

Forum Pro

Similar threads

Keyboard shortcuts