bokeh – the quality of blur

bokeh – the quality of blur

Bokeh is the term used to describe the quality of background blur in a photo,

i.e. how pleasing the blur looks of the background areas. Since the softness of the background blur is usually more important than how the foreground items are blurred, bokeh usually relates to the background blur.

The bokeh of a lens is influenced by numerous factors, including
– the lens design,
– specifically, how spherical aberrations are corrected,
– the number of blades in the aperture mechanism,
– focusing distance,
– the actual aperture used will also affect bokeh to some extent,
– the distance of the out-of-focus objects,
– and in the case of the Nikon DC lenses, by how certain aberrations are selectively introduced.

Bokeh is usually described as being subjective, and it largely is.  However, when you’re able to recognize the difference between good bokeh and poor / harsh bokeh, then it becomes less subjective I believe. When you see good bokeh, you’ll recognize it. Same with bad bokeh.

To illustrate how good bokeh appears, and what poor bokeh looks like, I had set up this simple shot.


It isn’t art, so don’t critique the photography – I wanted those random out-of-focus items in the background.

I used two lenses here, comparing the Nikon 28-105mm f3.5-4.5 with one of the very best lenses that Nikon has .. the 105mm f2 DC. The 105mm DC lens has superb bokeh, so it should be quite apparent in comparison photographs why I didn’t like the 28-105mm lens in this respect.

Here’s the set-up shot .. my daughter in our backyard, with some back-lighting and arbitrary
out-of-focus clutter in the background. The general photo is reduced in size, but the other two are 100% crops, shot with low sharpening on the D2H, both lenses at f5.6

As you should be able to see from these crops, the 28-105mm zoom has a harsh bokeh ..
the out-of-focus areas look ‘wiry’, whereas the 105mm DC lens has a very smooth looking out of focus background.

The 100% crop from the 105mm f2 DC ..

.
.. and the 100% crop from the 28-105mm zoom at 105mm setting ..

(The part of the railing that is visible, seems to be clearer in the one shot, but that was because she moved slightly and I had to refocus on her eyes. I did try to keep things as consistent as possible, but little kids aren’t inanimate. The photos should still serve as a comparison.)

Anyway … this was one of the reasons I sold the 28-105 mm lens.
The bokeh was harsh. And yes, the client might not notice, but I do.

.
bokeh & depth-of-field

I frequently see photographers confuse shallow depth-of-field (DoF), and call it bokeh.  And worse, just because they achieve shallow DoF, talk about “getting more bokeh”.  So I would like to emphasize this point .. shallow depth-of-field is NOT the same as bokeh.  Bokeh is about the quality of the background blur, and not directly about the depth-of-field.

Bokeh is a function of the optics, and specifically describes the quality of the out of focus areas – whether it is smooth or harsh. Therefore, you don’t get “more bokeh” by going from f5.6 to f2 .. but you do get shallower depth of field.

Also, phrases like “more bokeh”  are nonsensical terms.  A description such as “more pleasing bokeh” .. that makes sense. But, going from f5.6 to f2 doesn’t give you “more pleasing bokeh” … it just gives you shallower depth of field.

But .. as someone pointed out to me, this is mostly true.
While it is true that a given lens will maintain certain optical traits across its aperture range – such as how in these examples it renders background highlights – there are some characteristics, usually uncontrolled aberrations, that are only visible at wider apertures: soft corners, coma, vignetting, etc., that can all contribute to what might be considered a “more pleasing bokeh.”

Using a different LENS with different characteristics will give you more pleasing bokeh than a lens with harsh bokeh, more so than a change in aperture would.  So it would still be true to say that bokeh isn’t the same as shallow depth-of-field.

All of which kills me when people fawn over how awesome the bokeh is of their Canon 50mm f1.4 or Nikon 50mm f1.4 lenses .. both known for poor bokeh. Just because the image was shot at f2 or wider, and with a background so far away and defocused that you don’t actually get to see ANY background detail, doesn’t automatically give you great bokeh.  You have to see the way the lens handles out-of-focus background areas before making that judgment.

Examples of lenses which will give you great bokeh:
Canon 24-70mm f2.8
Nikon 28-70mm f2.8 and the Nikon 24-70mm f2.8

And then of course, you have the kings of beautiful bokeh:
Nikon 135mm f2 DC
Nikon 200mm f2 VR
Canon 200mm f2 IS
(there are many others)

Lenses that have crap bokeh, no matter what you do:
Nikon 50mm f1.4 AF-D
Canon 50mm f1.4
Nikon 28-105mm 3.5-f4.5
Canon 24-105mm f4

68 Comments, Add Your Own

  1. Alex says

    Ah… After re-re-re-watching my picture and reading those lines I think to understand what you wanted to say…
    I have taken this picture at f1.4 with the Canon 50mm f1.4 and the 400D. Now I understand what you mean with the difference of Bokeh and DoF…
    Thank you for this!

    http://picpirates.deviantart.com/art/Toneworx-2-107641051
    (klick on the image for larger view and please feel free to comment if you want to)

    ~Alex~
    [Germany]

  2. kate w says

    Heh, I just got a D700, so I’ve been raving about the bokeh on my 50 mm 1.8 lens relative to the (pretty much non-existent) bokeh on a DX body. But now I can see it’s not so great… oh well.

  3. says

    Kate ..

    A crop sensor doesn’t affect the bokeh. It will affect the depth of field, but it won’t affect the bokeh.

    Here is an image I took a few years back in London. And no, she isn’t a bride. She’s a mime. The second image is a 100% crop of the background to show how smooth the out-of-focus areas look.

    It was shot with the Nikon D2x and the Nikon 85mm f1.4 AF-D

    Neil vN

  4. Derrick says

    Thanks for this. Just getting serious about this as a hobby and was confused by the seemingly broad use of the term.

    Just the distinction that it is a qualitative assessment vs. a quantitative assessment provides great clarity (reverse pun not intended).

    Just stumbled on your site last week and spent the better part of the week reading through all your archived posts. Having tons of fun experimenting with all the advice you have shared.

  5. says

    Frank, I don’t think poor bokeh is something that can (easily) be fixed in Photoshop. Slapping on a lot of gaussian blur and selectively adding it as a layer might mask it, but you’d be better off starting with a lens that displays great bokeh in the first place.

    Neil vN

  6. Jose says

    Neil – Thanks for clarifying the difference between DOF and bokeh. I think the one critical aspect that needs to be emphasized is that bokeh is highly subjective.

    In my opinion, the bokeh provided by the Nikkor 50/1.8 is great, even in a DX sensor. I agree that there are better lenses in terms of good bokeh such as the 28-70/2.8 or the 70-200/2.8, but for the price the 50/1.8 produces very creamy bokeh.

    Lenses that I have found to have poor bokeh are typically the zooms with variable apertures (e.g., f/3.5-5.6). Consequently these are the same lenses that are not capable of producing shallow DOF and why people associate bokeh to DOF.

  7. says

    … however, sensor size does not affect the bokeh at all. Bokeh is an optical consideration. The same way that cropping your photo a little tighter won’t affect how the background appears .. using a crop-sensor camera won’t affect the bokeh.

    Neil vN

  8. says

    Tomasz

    Looking at the photographs in isolation, the backgrounds appear pleasing enough, although I can see that the bokeh isn’t smooth. If you did a comparison image with an other lens than the Canon 24-105mm f4, you’d most likely find the background seems smoother. But as it is, on its own, very few people are likely to comment on the background itself as it appears there.

    Neil vN

  9. William Rodriguez says

    Over the years I have read a lot, in Internet forums, about “bokeh.” I have read a lot also on depth of field. To my understanding, both are dependent on the lens aperture and still it is very difficult for me to tell the difference.
    One of the best lenses Nikon had in the past for portrait photography was the 105 f2.5 AIs Nikkor. It was very popular with portrait photographers but it did not necessarily have a great bokeh. I have an older version from the 60’s and it is still the lens I reach for when I want to photograph portraits.
    I am in total agreement that bokeh is very subjective. I look at the photographs of your daughter, that you used as an example, and I admit the bokeh of the 28-105 AF Nikkor does not bother me. It could be my ignorance! By the way, I have used that lens for portraits at f8-f11 and I have been very pleased with my results.
    Something similar happens with diffraction. I began to pay attention and got “scared” using my optics beyond f11. Today I use the aperture I believe will do the job and I am now happier than I was in the past.
    Yes, I am not a professional photographer.

  10. Serge Van Cauwenbergh says

    About the crappy bokeh with the Nikon 50mm f1.4 AF-D… do you mean the older version or also the new AF-S version?

    What about the Nikon 105mm f/2.8 AF-S VR?

  11. says

    Serge ..

    I just received the AF-S version of the 50mm, but haven’t had time to really play with it yet, but the bokeh will be one of the first things I’ll check out.

    Similar with the 105mm f2.8 VR

    Neil vN

  12. Dennison Uy says

    Hi Neil,

    I was surprised when I read what you had to say about the Nikon 50mm f1.4 … I guess that’s what separates the experienced from the amateurs. I am planning to buy this lens, partly because of its shallow DoF, partly because it’s supposed to be very sharp, and partly because it’s a relatively inexpensive prime lens. Having said this, is there a similar lens that can compete with the Nikon 50mm f1.4 in terms of sharpness, DoF, and price plus gives great bokeh?

    Many thanks,
    Dennison

  13. says

    Dennison .. definitely buy the lens, and use the lens. Bokeh shouldn’t be the definitive reason why you buy or don’t buy a lens .. unless it is meant to be used in a specific way.

    For example, a 200mm f2 lens with poor bokeh would be a disaster since the lens will nearly always be used to isolate the subject against the background at f2 … and here the bokeh will be an important aspect of the final image.

    About which 50mm lens I’d recommend .. I’m not au fait with all the possible 50mm lenses to make such a suggestion, unfortunately.

    Neil vN

  14. Ovidiu Suteu says

    Hi Neil

    is there any relation between the lens noise and bokeh? I have a Nikon 24-70 f/2.8 which has in my opinion a great bokeh. The nikon 80-200 f/2.8 on the other hand, despite the fact that presents a nice bokeh also, seem to have a higher lens noise.

    24-70 f/2.8

    80-200 f/2.8

  15. says

    Ovidiu .. lens noise? As in the sound the lens makes when it focuses?
    If that’s what you mean .. then there will be no effect on the bokeh, since bokeh is dependent on the optical design.

    Neil vN

  16. James says

    Great article Neil! You always seem to post things that other people would normally never see.

    I just have something to say about the matter. I would expect the bokeh to be better on a lens (either a zoom or prime around 100mm or further) to produce that smooth effect because these lenses are typically being used for headshot type work. When you go to print that headshot for a client, the area of bokeh is much more apparent because it is magnified in a sense (if printing an 8×10 the subjects face is almost in the entire frame, so thus you would see more of the bokeh area).

    My point is, I don’t think many people should be putting off buying a 50mm 1.4 lens from any manufacturer because this lens is typically not used for a headshot. I typically use mine for mid-length to full body portraits, so if an 8×10 were to be printed, the bokeh area would not be magnified as much as with a headshot.

    Therefore, I would require a longer lens to have better bokeh before getting picky about a shorter length lens.

  17. says

    James …

    I completely agree with your assessment that requiring fantastic bokeh from a lens becomes more critical the longer the lens.

    Neil vN

  18. Alvin says

    Hi Neil! This is more of a query rather than a comment. I am thinking of getting an AF Nikkor 35mm, f/2 lens and use it as a 50 mm equivalent for my D80 (DX). I really never got to consider the bokeh that lenses produce until I read your article. Anyway, do you have experience regarding the bokeh of this lens? The reason I ask was before considering this 35mm, I was contemplating on getting a 50mm, f/1.4 which you described as not producing a good bokeh. Thanks!

  19. Dennison Uy says

    Neil and James

    Thank you for your insights … I see the point of using the lens for a specific way. I would definitely never use a 200mm lens for a landscape shot that’s for sure!

  20. Stephen says

    Neil,
    This is the best explanation of Bokeh I have ever read. Now I understand what Bokeh is on a non-mathematical level and how to gauge its quality. Now, I can look back at old photos and check out the backgrounds more carefully.

    I have read that the Nikon 70-200mm f2.8 has been regarded as having good bokeh. I didn’t notice the backgrounds before, but now looking back at two of my photos in the past, I can see a smooth and creamy background blur.

    image 1

    image 2

    I have a 24-70mm f2.8 but I haven’t really taken any headshots with it, but I would have to agree that the shots I have previously taken, the bokeh is of excellent quality.

  21. Eileen says

    Serge,

    I have the Nikon 105mm VR and in my opinion it has very good bokeh, with very smooth, creamy out of focus areas (as you’d expect from a macro-specific lens). I’ve just looked at one or two my my pictures taken with it and compared to Neil’s 100% crop from the 85mm above and am still happy with my lens.

    Eileen

  22. Kevin C says

    The Nikkor 85mm f/1.4 as well as Canon 85mm f/1.2L both produce incredibly pleasing bokeh and are among favorites with wedding photographers. Some people love the Sigma 50mm f/1.4 compared to the Nikon/Canon 50mm f/1.4 but there are those who simply hate it. I wonder what everyone’s take is on the Sigma 50mm f/1.4 (and its cousin 30mm f/1.4)?

  23. says

    Neil –

    I’m still loving this site. I, too, confused bokeh with dof for a while. But after hearing a lot of knowledgeable people use bokeh, I realized it was more about quality. Anyway, how do you pronounce bokeh? I’ve always wondered. I’m afraid to discuss it with anyone other than a forum because I don’t like mispronouncing words.

  24. Dan says

    Hi Neil!

    Your site was past on to me by a co-worker and I have found it very useful. I have only looked at it for about 30min and have already learned a lot…I was one of those people confused about the difference between bokeh and dof. I am a at novice at best but am excited to become so much more one day and am sure your site will be a great start.

    Thx!,
    Dan

  25. Winston Mattis says

    I have a D300 and want to get the Nikon 50mm f/1.8 instead of the f/1.4, because of price.Do I wait and save for the f/1.4?

  26. says

    Winston, the f1.8 is a fine optic, but often under-rated. Itis very sharp.

    However, in relation to this post being about bokeh – neither of those two lenses have great bokeh – if that is what you were in fact asking about.

    Neil vN

  27. Dave says

    I admit that I have been substituting bokeh for the amount of background blur from depth-of-field until I thoroughly read your article. Now that I know the difference, I’m almost embarrassed to think back to the people I’ve spoken to recently (many of them professional photographers) who must have been too polite to correct me. Thank you for the clarification and for posting this article!

  28. Mark C. says

    Does the number and shape of diaphram blades have an effect on Bokeh?

    If it does, can you predict how a lens will perform; i.e. more blades, or even more curved blades, meaning better quality Bokeh?

  29. says

    Mark .. While the number of aperture blades is a contributing factor that helps determines the bokeh of a lens … I think other factors, and primarily how spherical abberations are corrected, will have a stronger effect than the number of blades.

    Neil vN

  30. sebastien says

    Just out of curiosity when you shot your daughter with the nikkor 105/2 DC did you use the DC functionality (as in did you set it up to R/2 or F/2), cause i do have that lens and if the background is “noisy” i almost always set it to R/2.

  31. Carol says

    Thanks for this great explanation as I was really wondering about the difference between DOF AND BOKEH.

  32. Canaan says

    Thank you for listing some lenses which exemplify good & poor bokeh. Personally, I was looking for a reason to purchase the Canon 24-70 over the 24-105 and this may be all the justification I need ;)

  33. Kay says

    Neil, what do you think about the Canon 85mm 1.8 (non-L version) in regards to bokeh? It has very favorable reveiws @ BH. And the price is much better than the 70-200mmL f/2.8 IS lens, which is why I have been considering purchasing it! I have the 50mm1.4 & see what you mean about the quality of bokeh it produces. Anyway be intersted to hear your take on the Canon 85mm 1.8 for bokeh is! Thanks;~)

  34. says

    Kay, I did own the Canon 85mm f1.8 for a while, but never specifically checked its bokeh, and it would be a hard task trawling through my archives now for images shot with that lens.

    By all accounts the bokeh of that lens is very good.

    Neil vN

  35. Tex says

    Neil,
    I really enjoyed your explanation and examples. Within my own collection of Pentax lenses, I have some with very smooth and pleasing bokeh and one or two that produce a harsh distracting bokeh effect.
    My question is about lenses such as the Cosina 55mm/1.2 which i purchased mainly because of the very artistic bokeh effect it renders. The bokeh, mind you, is not at all “smooth” by your definition. On the contrary, it seems to create a series of overlapping ovals which turn a shallow DOF shot into something akin to a watercolour painting. OTOH, to my eye it is very pleasing in the right situation.
    Has my photographic “eye” just not matured yet or is there a respected place for this type of lens?? thanks.

  36. Jury says

    Hi Neil,
    I’ve been reading your pages and enjoying your photos, your site will allways be a reference to me(often I’ve to read it more ten once)…..keep it up.

    But I wandered, can I achive the same(almost) bokeh and such a good and brightley photo’s as you have here on your site….with my AF-S Nikkor 18-105mm VR 3.5-5.6G ED DX…on a nikkon D90?..have them now for almost a year.
    For the time being I cannot affort another more expensive objective…..

    I want to get so close to get brightly photos and ones a while nice bokeh…with this objective….

    thanks for being zo clear..

  37. says

    Jury, I have no experience of the Nikon 18-105mm VR 3.5-5.6 lens, so I can’t comment on the bokeh.

    As for depth-of-field, with a fairly slow aperture, and on a crop sensor camera, you won’t get fantastic shallow depth-of-field. It’s the nature of using a small aperture.

    Neil vN

  38. Anoop nair says

    Neil

    Any Bokeh Experience with Nikon AF-S Zoom-Nikkor 70-200mm f/2.8G ED VR II lens ? I am Planning to get the VR II Version. I do own a Nikon D300& D3X. Need some advice.
    Thanks
    Anoop

  39. Artur Ocubaro says

    Hi Neil!

    Beautiful photos, magnific explanations……..thanks!

    What is your opinion about Canon 85 f 1.2 regarding bokeh? And a question that may be redundant or repetitive but Id really like to hear your opinion…..Im going to buy the 5D MII and definitely the 24-70 2.8, but I m also really thinking about the 24-105 because there is a 350 dollars discount when bought with the 5D. Anyway I ll buy the 24-70, but what do you think about the 24-105 as a allday lens because of the much less weight? Would you use that?
    Thanks again!

  40. says

    Artur, the Canon 85mm f1.2 (both AF versions) are rightfully regarded as wonderful optics. Their bokeh is just wonderful. Especially on a camera like the 5D which has a tendency to vignette to the corners, the 85mm f1.2 can give an ethereal look when used wide open.

    The Canon 24-105mm f4 is a great all-round lens with excellent optical performance. But don’t expect the bokeh to look nice.

    Neil vN

  41. Artur Ocubaro says

    Hi Neil!

    Thanks for your opinion, I really appreciate. I ve been wondering how do you find the time to do all your work and keep answering all the questions in your site? That’s amazing and very respectful! Thanks.
    And what do you think of the fisheye lenses? I do not think that you ve used in your esplendid work, do you have any restrictions about them?
    Another question, when are you going to publish another book (whatever subject book)?

  42. says

    Artur .. I do use the fish-eye lens on occasion, but I do feel that it can easily look gimmicky if over-used. Either way, I do believe it’s a lens that needs to be in any photographer’s bag.

    Neil vN

  43. Jannine says

    Thank you for a brilliant topic. I have often wondered what bokeh was, i hear people speak about it,but didn’t like to ask. Neil i love this site & your book. The thing is all the subjects are interesting, so much so i don’t know where to look first. I keep flitting from one article to another.

  44. André P. says

    Great explanation. My mind was already set on shallow DOF = Bokeh… But, as always you make me that “aaaaaaaaaaaah… of course… how stupid” feeling.

  45. says

    Thank you for bringing this point to the surface. The term bokeh has become the buzz word of the digital world…and used incorrectly 95% of the time.

  46. Renato Costa says

    Very nice article Neil.
    Worth to mention the existence of Minolta/Sony 135mm STF 135mm f/2.8 [T4.5], with its apodization filter that provides a very high quality bokeh.
    So great that made me buy a Sony body, only to use this gem.
    Regards.

  47. Jeremy T says

    Hi Neil,

    You’ve said a few times in the comments that sensor size doesn’t affect bokeh quality. However, as the bokeh is affected to quite a large extent by the depth of field, this may not hold true – the reason behind this of course being that depth of field is affected by the size of the focal plane.

    If you consider that, when using lenses of the same equivalent focal length (and for this example, say with equal optical quality) to obtain the same FOV on full frame and APS-C sensor bodies, aperture needs to be changed to accomodate the depth of field. Obviously there is a noticeable difference in the depth of field.

    The point is, anyway, that this change in DOF would affect the bokeh, would it not?

  48. says

    If everything else stays the same .. point of view; aperture; etc .. then the cropped sensor is just that – a crop of a (hypothetical) larger image. So the bokeh has to be the same then.

    Neil vN

    • Thorsten says

      I assume, that Jeremy (and other people asking questions like this) are wondering, because crop sensor to them automatically means, that you use different lenses. So while I would use a 85mm AF-S 1.8 on my D700, another person would use a 50mm AF-S 1.8 on a D7000 with crop sensor to achieve a simmilar picture.

      And then of cause you will see the difference. Both pictures will look quite simmilar, but if you look in the background, you will find, that the D700 picture is much smoother than the D7000 picture, for the simple reason, that the 85mm lens on the D700 gives a much nicer bokeh than the 50mm on the D7000.

      As stated above you can generally expect better bokeh from longer lenses. Also the DOF will get much smaller the longer the lens is. Take a point and shoot camera with a 5mm sensor, set its lens to an equivalent 50mm, take a picture with the aperture wide open and you will see, that everything is in focus. The bigger your sensor/film, the longer the lens you use for the same framing, so the smaller the DOF and at least usually the better the bokeh. So one can say that if portrait is what you mainly do, you need the biggest sensor area practical. Using a 50mm and a D7000 will give better results than a point-and-shoot, using a 85mm and a D700 will bring better results than the D7000 and using a 150mm on a 6×6 film camera will bring better results than the 85mm on the D700.

  49. Robert Potter says

    I bought an old Olympus 50mm Zuiko F1.4 lens off ebay for $100USD and fitted it with an adapter ring to use it on my Canon 40D. I also bought a spilt focus screen to help me do manual focusing.

    I believe that this lens gives you one of the best bokeh looks even compared to expensive modern lenses.

    Take a look at this shot I took using the Zuiko 50mm F1.4 lens at F2.

    There are some awesome cheap manual lenses with great bokeh available on the second hand market.

  50. Stefon says

    Very good article that explain a lot about bokeh and separate the reality from the “urban legend”…
    Always a pleasure to read your site.

  51. Phil says

    With all due respect to Robert Potter, I believe that the bokeh on your pic is an example of bad bokeh. I get that wiry impression from it that Neil mentioned in his article. For better perspective, try to look at a pic taken with a Canon 135/2L where the transitions are much smoother. Or try an 85/1.8.

    Please understand that this in not a critique of your skills but fair commentary on the properties and characteristics of the lens. I don’t think any amount of skill can get good bokeh out of a lens with bad bokeh (if I read Neil’s article right). Bokeh is what it is.

    As far as the rendering of the shot goes, I happen to think it was done very well. Colors came out great and the subject matter stands out from his background. FWIW I’m also still confused as to why it should be construed as “good,” “neutral” or “bad” bokeh when all of it is subjective. True art should be a product of the artist, not the instrument.

  52. Matt says

    @Phil ‘bad’ is bright edges, bright centres, coma (as previously discussed). IMO, the boke of the 2/105 in the demonstration is ok but not stellar (especially considering that the shot is at f5.6). I would rate any Sonnar formula lens (e.g DDR Zeiss Jena) or Angenieux as better than this. Thanks for a good article and blog. Best, M

  53. Robert Potter says

    @Phil There are thousands of variations of bokeh you can’t just say only X,Y and Z type lens have it. The effect each one gives is down to each individual persons taste. I have a pile of digital photos shot with the Olympus 50mm Zuiko F1.4 giving amazing bokeh and clients loved them all and paid me in full. By the way the word “bokeh” comes from the Japanese language and literally signifies something which is unclear or out of focus.

  54. mark says

    In regards to the two images. The one with the bad bokeh is sharper than the good bokeh. SO are you saying we give up detail for blur?

  55. says

    You absolutely can NOT make any of those conclusions from the photos at the top. There isn’t enough information for you to do so, nor comparative images. With those crops, you have no idea if she changed poses, to cause the railing to be more out of focus, or whether I had perhaps missed focus a little.

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