bokeh – the quality of blur
[ this is an update of an article which has previously appeared on this website ]
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 abberations 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’, wheras 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 emphasise 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 know 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 judgement.
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
Alex Said,
January 10, 2009 @ 4:36 am
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]
paurullan Said,
January 10, 2009 @ 6:35 am
Even that aperture does not give you better bokeh there is a thing that increasing f values improves: the coma.
When you have an awful lot of unfocused lights for bokeh you may find wrong degradation pattern in some of them. This is called coma and you can improve or remove it just moving one or two full stops.
For example: http://www.flickr.com/photos/paurullan/3092999912/in/set-72157610912203822/
kate w Said,
January 10, 2009 @ 8:23 am
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.
Neil Said,
January 10, 2009 @ 8:35 am
Derrick Said,
January 10, 2009 @ 9:06 am
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.
Frank Said,
January 10, 2009 @ 9:46 am
Is (bad) bokeh something that can be corrected in post-processing (e.g. Photoshop)? If so, how to do that?
Neil Said,
January 10, 2009 @ 10:03 am
Jose Said,
January 10, 2009 @ 1:53 pm
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.
Neil Said,
January 10, 2009 @ 2:01 pm
Tom K. Said,
January 11, 2009 @ 2:10 pm
Alien Skin’s Bokeh software is phenomenal…….however, there is nothing like a Canon 135f/2L on a Canon 5D for some serious “real” bokeh.
Here’s the link to the Alien Skin Bokeh software: http://www.alienskin.com/bokeh/index.aspx
Tomasz Said,
January 11, 2009 @ 2:19 pm
Neil – really great website. Congratulations :)!.
I’m quite new to bokeh idea. Could you, pls check an image of cotonaester I took with Canon 5D Mark II with 24-105 mm f4 lens. Waiting your opinion.
http://tomaszminkina.blogspot.com/
Neil Said,
January 11, 2009 @ 6:03 pm
William Rodriguez Said,
January 12, 2009 @ 4:54 am
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.
Harry Simpson Said,
January 12, 2009 @ 1:07 pm
Hi Neil,
So you’re saying good bokeh is smooth and creamy blur for the most part?
Harry
Neil Said,
January 12, 2009 @ 2:25 pm
Serge Van Cauwenbergh Said,
January 12, 2009 @ 4:52 pm
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?
Neil Said,
January 12, 2009 @ 10:18 pm
Dennison Uy Said,
January 13, 2009 @ 4:50 am
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
Neil Said,
January 13, 2009 @ 6:27 am
Ovidiu Suteu Said,
January 13, 2009 @ 10:06 am
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
Neil Said,
January 13, 2009 @ 2:21 pm
James Said,
January 13, 2009 @ 7:00 pm
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.
Neil Said,
January 13, 2009 @ 9:33 pm
Alvin Said,
January 14, 2009 @ 7:37 pm
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!
Neil Said,
January 14, 2009 @ 11:34 pm
Dennison Uy Said,
January 15, 2009 @ 4:23 am
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!
Stephen Said,
January 15, 2009 @ 9:48 am
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.
Eileen Said,
January 17, 2009 @ 9:30 am
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
Kevin C Said,
January 22, 2009 @ 9:06 pm
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)?
Deb Cull Said,
January 26, 2009 @ 12:06 pm
Neil –
I’m still loving this site. I, too, confused bokeh with dof for a while. But after hearing a lot of knowledgable 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.
Neil Said,
January 26, 2009 @ 12:31 pm
Dan Said,
January 26, 2009 @ 6:06 pm
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
Winston Mattis Said,
February 20, 2009 @ 12:03 pm
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?
Neil Said,
February 21, 2009 @ 4:18 pm
Dave Said,
March 22, 2009 @ 10:05 am
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!
Mark C. Said,
March 24, 2009 @ 1:15 pm
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?
Neil Said,
March 24, 2009 @ 3:53 pm
sebastien Said,
March 29, 2009 @ 4:31 pm
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.
Neil Said,
March 29, 2009 @ 6:40 pm
Carol Said,
June 1, 2009 @ 11:42 am
Thanks for this great explanation as I was really wondering about the difference between DOF AND BOKEH.
Canaan Said,
June 3, 2009 @ 12:53 pm
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 ;)
Kay Said,
June 3, 2009 @ 3:33 pm
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;~)