Creating Background Blur in Your Photographs

Example of using a wide open aperture to achieve background blur in your picture.
Sometimes you are taking photos inside in low-light. Using a wide-open aperture will help your camera make a better exposure. The camera won't need to use as long of a shutter speed or as high of an ISO setting. So you kill two birds with one stone - you create the background blur you want and you get a better exposure too!
Example of picture taken with wide open aperture to maximize the background blur
My daughter at the State Fair of Texas. This photo was taken using an aperture of f/2.8, which, as you’ll read about in tip 1, is very important. In addition, I used a focal length of 80 mm, which is addressed in tip number 4.

When you have a definite subject of your photograph, you usually want it to appear as sharp as possible while at the same time making the background blurry. That will make the subject pop and minimize distractions in the background. Plus it just looks like a pro move, doesn’t it? Virtually all portraits are shot this way. In fact, any shot your take with people in it will usually benefit from blurring out your background. When you are just starting out, adding background blur to your photos will separate you from the total beginners.

But how do you do it? It is pretty easy, really, and just involves changing one control on your camera. In this article, I will show you how to do it, as well as some ways to accentuate the effect.

Before we get started, let’s talk about nomenclature.  You will sometimes hear background blur referred to as “bokeh” and then hear photographers argue about how to pronounce it. As you know, if you’ve been around this site for a while, I’m all about discussing photography in plain English. Usually by that I mean I’m trying to keep things really simple, but I suppose it also means that I use English terms. So I’m just going to call it “background blur.” I don’t think the term “bokeh” adds anything.

With that said, let’s get started. In explaining this to you, I’m going to show you 4 tips for creating background blur. But let me be clear – the first one (using a wide aperture) is by far the most important thing. Sometimes that is all you need. The rest of the tips are just to make sure that the wide aperture works for you.

Example of picture taken with widest aperture setting to maximize background blur.
A photo of my daughter Elizabeth on a trip to Paris (France, not Texas!). Taken using an aperture of f/4.0 (the widest setting for this lens). I also used a focal length of 96 mm. You can see that I was close to my subject and the background was far away, to maximize the effect of the shallow depth of field (see tips 2 and 3).

1. Shoot With a Wide Open Aperture

I’ve already given this one away, but the way you create background blur is to simply open up the aperture of your lens as wide as possible. That’s all there is to it.

If you have been shooting for any length of time at all, this is old news to you. But if you haven’t, you may not know how to change your aperture (or even what an aperture is). Anyway, the aperture is the hole in the back of each lens that allows light to enter the camera. Even though the aperture is on your lens, it is controlled by the camera. I cannot tell you how to change the aperture on your particular camera because the controls on each camera are different. You will need to dust off your camera manual (or find it online if you no longer have it) and it will show you have to change the aperture sizes on your camera.

What is happening when you make the aperture larger or small is that, in addition to letting more of less light into your camera for an exposure, it is changing something called the depth of field of your pictureDepth of field refers to how much of the picture in front of or behind the point at which you focus is sharp. In other words, start with the fact that wherever point you set your focus on will be sharp in your picture. Sometimes things fall off to out-of-focus very quickly, and sometimes not so quickly. The aperture is what controls this effect.

Again, if you have been shooting for a while, this is probably old news. But if not, spend a few minutes getting familiar with the concept of depth of field (start with this article). Typically you will want a shallower depth of field for something like a portrait, but a deeper depth of field for a landscape shot.

The upshot of all of this is that the larger the aperture of the lens, the shallower the depth of field. That means that when you use a large aperture for a picture, where you focus will be sharp, but things will fall off to an out-of-focus condition very quickly. That’s what you want here. You want your subject to be sharp, but you want the background to be blurry. Therefore, open the lens up to its widest aperture setting. There is no downside to doing this (if you want a shallow depth of field) because opening up the aperture lets more light into the camera, which makes it easy to use a fast shutter speed and lower ISO.

Some Peculiarities of Aperture

Aperture/depth of field is one of the hardest things for beginning photographers to get their heads around. Actually, it is probably the most confusing part of photography, period. It is measured in a weird way, and different lenses have different ranges of aperture settings.

One such peculiarity of aperture/depth of field is that as the aperture gets larger the measurement (which is a number that starts with an “f/”) gets smaller. Therefore, to get the most background blur, you want to use the smallest f/number you can get. The number is a reciprocal, and how it is calculated will do nothing to help you understand this or improve your photography, so let’s not worry about it. But you need to remember that the larger the aperture, the smaller the f/number (and vice versa).

Another peculiarity of aperture/depth of field is that the range changes depending on what lens you are using. Most zoom lenses open up to about f/4.0, and the top zoom lenses open up to f/2.8. Prime lenses open up even further. It is not uncommon for a prime lens to open up to f/2.0 or smaller. Just look around the front ring of your lens and it should tell you the largest aperture for that lens. In fact, most lenses are defined by the focal length and the largest aperture setting, so anything you can find about your lens will tell you the largest aperture size for it.

Anyway, opening up the aperture to its maximum setting (smallest f/number) may be all you need to do to get some nice background blur. The remaining three tips will help you maximize the effect though.

Example of using a wide open aperture to achieve background blur in your picture.
Sometimes you are taking photos inside in low-light. Using a wide-open aperture will help your camera make a better exposure. The camera won’t need to use as long of a shutter speed or as high of an ISO setting. So you kill two birds with one stone – you create the background blur you want and you get a better exposure too!

2. Create separation

The point of the wide open aperture is to decrease your depth of field.  Again, that means you are decreasing the amount of space in front of or behind the point of focus that will still be sharp.

Having a narrow depth of field won’t do you any good, however, if your subject and background items are on the same plane. When the camera focuses on something, that thing and everything else the same distance away will be in focus. If your subject and the background are both the same distance away, then even with a shallow depth of field, they will both be sharp. You can open up the aperture all you want and create the shallowest depth of field possible, but it won’t matter. You will have no background blur.

You need to create some distance between your subject and your background. That may be easier said than done if you are photographing an unmovable object like a statute or a tree. But if your subject is a person, move them around a bit to create the separation you need.

Creating this distance between subject and background lets the background blur kick in to its full effect. If you find you are using a wide aperture but not getting the effect you are looking for, this tip will usually fix you up.

Example of using a wide open aperture to achieve background blur in your picture.
Sports photography is another context when blurring your background is a great technique. Usually, you care nothing about the background and want it burred out. In addition, you want to use as fast of a shutter speed as possible in order to “stop the action.” The wide open aperture, in addition to creating background blur, lets in a maximum amount of light so you can use a faster shutter speed.

3. Get Close to Your Subject

Related to the prior tip, another way to create maximum background blur is to get close to your subject. Basically, all you are doing is pulling the point of focus closer to you. That means that there is more space for the sharpness to fall off as it moves toward the background.

Remember that in the prior tip, I mentioned that it is sometimes difficult to move your subject. But it is usually not difficult to move yourself. Remember this tip when you need a way to create separation between your subject and background to maximize background blur.

4. Use Longer Focal Lengths

Finally, longer focal lengths will result in a shallower depth of field. If you have a zoom lens, stand back from your subject and zoom in. Or perhaps just stay where you are and zoom in anyway, which usually results in better compositions. Either way, when you are using a wide aperture, the longer focal length will help maximize the effect.

Advancing From Here

When you are first starting out in photography, the ability to create background blur in a picture seems a little like magic. As this article shows, however, it is ridiculously easy. Just make sure the aperture is opened up and you have separation between your subject and the background. You’ll be a master in no time.

To understand this concept further, if you haven’t already done so, this is a good time to bone up on aperture and depth of field. Check out this article to do so. While you are at it, you might check out the exposure section of the site, which covers lots of things related to aperture, shutter speed, and ISO.