Often, in my lens reviews, I’m guilty of talking about a lens with “good bokeh” or “bad bokeh” without first providing a disclaimer: The quality of a photo’s background blur is only partly due to your lens’s rendering. Other factors matter more – and many of them are well within your control.
Factors Influencing Out-of-Focus Blur
In no particular order, here are some of the main factors that can help or harm the quality of a photo’s out-of-focus blur:
- Aperture
- Focal length
- Lens rendering qualities
- Camera-to-subject distance
- Tones and textures within the background (and foreground)
- Subject-to-background distance (and subject-to-foreground)
There are a few other factors beyond this. For example, using a slower shutter speed in combination with some camera movement can change the quality of the out-of-focus blur. And on some cameras/lenses, there may be slight differences in the bokeh when using image stabilization or the electronic shutter. But generally, the six factors above are the most important, or at least, the most discussed.
When Bokeh Can Be Improved by Your Lens
I’m not trying to suggest in this article that a better lens has no effect on bokeh. Here’s a pretty clear comparison – thanks Libor for sending me these photos! – between two photos where a different lens was the only good way to improve the background blur of a photo. First is an image with the Nikon Z 180-600mm f/5.6-6.3 at its maximum aperture of f/6.3, versus the Nikon Z 400mm f/2.8 TC VR S at its maximum aperture (at least when the TC is engaged) of f/4:
For this photo, it was impossible to change factors like the subject-to-background distance, the camera-to-subject distance, or even the choice of background in the first place. After all, Libor could only see this owl through a small window in the tree branches. It simply wasn’t possible to move around the camera too much, so the best way to improve the bokeh was to change lenses.
In this case, the 400mm f/2.8 (at 560mm and f/4) offered a bit more than one stop of additional background blur compared to the 180-600mm f/5.6-6.3 (at 600mm and f/6.3), which was a meaningful difference in this photo.
These situations definitely happen. However, the difference is usually going to be no more than one or two stops of improvement with the wider aperture lens. Even the biggest difference that I can think of in the Nikon lineup – the 400mm f/2.8 versus the 28-400mm f/4-8 when both are used at 400mm – is a difference of three stops (f/2.8 versus f/8). You can do much better than that.
Improving Bokeh by Getting Closer
There are three major ways to improve a photo’s bokeh without changing your lens. The first is to adjust camera-to-subject distance. In particular, as you get closer to your subject, depth of field gets shallower and shallower. It’s why you can take macro photos with dreamy, creamy backgrounds even at apertures like f/8 or f/16.
I don’t begrudge a wildlife photographer for cropping. Sometimes that’s the only way to get the shot. However, if you routinely have to crop your photos significantly, be aware that you aren’t just losing resolution. You’re also losing a significant amount of background blur compared to what you would achieve by getting closer to your subject in the first place.
Here’s a comparison between two photos taken at different apertures: f/1.4 and f/4.5. That difference is about 3.3 stops, which you’ll recall is a little greater than the difference between the Nikon 400mm f/2.8 and the Nikon 28-400mm f/4-8. Anyone would expect the f/1.4 photo to have more (and better) background blur, right? Well, see for yourself in this pair of photos that Jason sent me:
Actually, it’s the photo at f/4.5 that has a softer background! And the reason why is that Jason’s camera-to-subject distance was much shorter in the second photo. He probably gained five or six stops worth of background blur by moving closer, which more than counteracted the 3.3 stop difference in aperture.
In other words, if you want a one or two stop improvement in your background blur, you can spend thousands of dollars on a more expensive lens. If you want a five or six stop improvement in your background blur, get closer to your subject.
But what if you can’t get closer – maybe you don’t like the closer composition as much, or maybe it’s a distant bird and you’re already as close as you can get? Is it time to spend $14K on a 400mm f/2.8?
Well, before you use our website’s affiliate links and make us rich, stop and think if there’s something else you can do to improve the background blur just as much, if not more. Specifically: finding a better background in the first place.
Improving Bokeh by Finding a Better Background
If you thought camera-to-subject distance affected bokeh a lot, wait until you see what you can do with a better background!
Either by changing your camera position or waiting for your subject to move, you can dramatically change the quality of the background blur in the image.
Take these photos, for example. The subject is about the same size in both images – AKA, the camera-to-subject distance hadn’t changed much – but the bokeh is far nicer in the second shot!
What gives? Well, it wasn’t the lens or aperture. Jason used the Nikon AF-S 500mm f/5.6 PF for both photos and captured them both at f/5.6. However, the background in the second photo is much better. First, it’s a lot farther away – and subject-to-background distance is a major factor in background blur. And second, it is simply a lot less busy and distracting, with fewer nearby textures to mess up the out-of-focus areas.
Here’s another, more subtle example of how a different background is enough to change the quality of a photo’s background blur:
Here, the background has gone from being relatively pleasant – but a little distracting – into a nearly uniform wash of dark green. In this case, there are three factors at play:
- The Kiskadee moved to a slightly closer branch for the second photo. It shows again how camera-to-subject distance can matter.
- Not only was the second branch closer, but the background behind it was farther away. That made it appear even further out of focus.
- Finally, the second background also had more uniformly colored plants in the first place! All of the plants were dark green, whereas the plants in the first photo ranged from bright to dark. Even if the two backgrounds had been equally far away, the second photo would have had smoother background blur because of this uniformity.
So, if you want to improve the bokeh in your photo, pay attention to your choice of background in the first place. How far away is it? Is it uniform in tone, or does it have a lot of different light and dark textures? The answers to those questions almost always matter more than your choice of lens.
Improving Bokeh by Changing Your Angle
There’s one other major way to change the quality of your background blur, and it’s my personal favorite. What do you do if you can’t get closer to your subject, and there’s no way to switch to a different background? Is it finally time to max out the credit card?
Not yet! Even if you keep everything else the same, you can improve the bokeh in your photo dramatically by using a slightly different camera angle, usually by shooting lower to the ground. This changes the effective distance to the background so much that it can be like blurring the background 10 stops or more.
Here, for example, the camera-to-subject distance has not changed much, and the scene is the same – the background is some grass behind the Eared Dove. However, the second photo has a much nicer appearance to the bokeh:
That’s what happens when you just change your shooting angle! All that Jason did differently here was use a lower camera position, effectively placing the background and foreground much farther away from the subject due to the camera’s new angle. The lens and aperture were identical. And no, Jason didn’t add any extra “lens blur” in post-processing :)
To me, this goes to show how much power you have over your photo’s background blur in a way that doesn’t depend upon the lens. It’s true that Jason could have spent several more grand on a 500mm f/4 and gotten a bit less depth of field in the first photo. But a lower camera position did all that and then some. I’d even argue that the light weight of the 500mm f/5.6 PF is what made it so easy to position handheld at ground level. In other words, the slower lens – with a PF lens element that has been accused of harming bokeh – directly led to better background blur!
Conclusion: One Last Example
I want to show you a final example that demonstrates the difference between my own (minimal) wildlife photography skills and Libor’s experienced approach.
First is a photo that I took with Nikon’s most expensive Z lens – the 600mm f/4 TC VR S, with the built-in teleconverter engaged. Second is a similar photo that Libor took with the F-mount 200-500mm f/5.6 with a 1.7x teleconverter. I shot my photo at f/5.6, and he shot his at f/8. Surely the wider aperture and the massive price difference between these two lenses means that my photo is better than his? LOL – no.
With this comparison, Libor proves that a $650 lens (roughly the 200-500mm’s price on the used market) can beat a $15,500 lens where out-of-focus blur is concerned, as long as the owner of the $650 lens uses the right techniques. Here, Libor achieved such an improvement simply by combining a closer camera-to-subject distance with a lower camera angle. The result was a far nicer photo and a much shallower depth of field than what I managed to achieve with the exotic 600mm f/4!
Hopefully these example photos, and the article as a whole, prove that a photo’s bokeh isn’t just about your lens. Often, the more important factors are the decisions you make as a photographer: your camera-to-subject distance, your choice of background, and your subject-to-background distance.
I won’t say that the lens is irrelevant. There are still many good reasons to go with a faster lens, and of course I’m going to continue showing bokeh tests in my lens reviews. But the next time that your finger hovers over the “buy” button, take a moment to think back on this article and decide whether the bokeh you’ve been seeking could be captured another way.
Good tips and reminders, Spencer, especially the idea of getting a low angle.
Thanks!
Sure thing!
Allow me to “correct” the title, Spencer. “Bokeh is less about aperture, more about distances”.
I give zero f**** about “circles of cunfusion” and all that snob conversation, btw.
Distances do make a bigger difference here than aperture. Aperture still makes a difference, but what matters a lot less is which specific lens you’re using.
If creamy backgrounds were my goal, I’d rather have a 50mm f/1.4 with “busy” bokeh over a 50mm f/1.8 with “smooth” bokeh, for example. But if you told me that I couldn’t move my camera or subject with those two lenses, I’d rather have a 50mm f/4 with the freedom to move around!
I’m old enough to remember a time when we didn’t talk about bokeh, in fact if I had read the term I would have assumed it was something to order in a Japanese restaurant. I frankly don’t get all the fuss about what something out of focus looks like. I mean, c’mon: it is out of focus. Aren’t we supposed to be looking at what IS in focus? Comparing one lense’s bokeh to another is like comparing the exhaust sound of two cars: is it that important? Does it affect the performance? Is exhaust sound indicative of engine performance? Maybe I’m going off the rails here and you folks will roast me, but shooting landscape and people and street, I really don’t give a hoot what the non-subject background looks like. Okay: roasting time!
No roasting from me, but I will disagree a bit. The way I see it, the entire photo matters, including the non-subject areas. Sometimes they matter even more than the subject, precisely because any distractions in those areas draw your eye away from the subject.
For a good example of how the same subject isn’t equally interesting with every background, Jason’s two images of the Eared Dove in the “Changing Your Angle” section of this article demonstrate it nicely. The changes in out-of-focus areas are what make the second image so much better than the first, at least to me.
No way, the out of focus area matters a lot. Actually, the out of focus area exists contrasts with what is IN focus. For example, let’s say you have two shots: a bird with beautiful feather detail but everything in focus, versus the same bird but with a blurred background. You’ll notice the detail of the bird more because of the out of focus area. Therefore, the out of focus area provides a contrast with what is in focus. And the quality of it will affect that perception.
The analogy between the exhaust sound of the cars in relation to engine performance is not accurate, because the exhaust sound can be modified by changing the muffler and not affect engine performance. But you can’t change the out-of-focus area of a photo without changing the look of the photo. And, we should ALSO keep in mind that Spencer’s article isn’t even about the subtle differences between two lenses in the same situation! In that case, your argument might hold more weight. It’s more about achieving good looking bokeh by changing the situation. For example, the difference between the 50mm f/1.8S and 50mm f/1.4 exists, but not TOO noticeable in most situations at the same aperture – but the difference between two different situations can be immense. I think the point is that no matter what the lens, you can get ugly bokeh from it and that definitely can be distracting!
Sorry to say this, but circles of confusion is not something you should be striving for in relationship to your subject. The first thing you learn, is to remove distractions to an image. If you have no choice, such as the bird in water, you can still reduce it, by stopping down more, since the longer lens’ exaggerates confusion the wider your setting. Bottom line, bokeh; it is an element that can be used, but not to be over used in telling your story.
There’s no need to say sorry, I agree with you that not all photos demand the shallowest possible depth of field! You’ll find that in a fair number of Libor and Jason’s wildlife photos, they’re stopped down a bit rather than shooting at maximum aperture.
That said, if the background is too busy or distracting, most photographers will want to do something about it. Whether that involves using a wider aperture or going through the techniques in this article, that’s up to you.
I disagree with that. In general, you shouldn’t strive for anything. But every picture is different. In some, the circles can look fine, and pretty, modulo taste of course. The good thing is you can choose. Take Libor’s bird in the water for instance, which to me looks like a gallinule but might in fact be a duck. If he were to stop down more, then the circles behind the bird would start to get quite small, and perhaps more distracting. And are they distractions? As for being overused, not too many bird images like this have lots of circles so I’d say if there’s one thing it isn’t, it’s not overused.
If I take a bad photo with a great lens, it hurts my confidence more. It’s nice to save money and excuses.
If nothing else, taking bad photos with expensive gear is a great signpost to show what skills to work on next.