A request I hear over and over from my students, is that they want to know how to create a beautiful, soft, blurred background like the image you see here. There is a big misconception among new photographers that you need to go out and buy an expensive lens with a really big aperture to be able to achieve such a look. While it is true that a larger aperture will give you a shallower depth of field, there are also two other factors involved that many people haven’t heard before or have forgotten. In this article I’m going to show you the three factors to creating the lovely blurred background and how you can most likely do it with the lenses you already own.
The three factors that affect background sharpness are:
- focal length of the lens
- distance between the subject and the background
So to demonstrate how this works I’ve created some example photos of a friend’s daughter (because she was a more willing subject than my husband). This first set of images was taken with her about two feet away from the front door of the house. The lenses used for all the example shots are: 16mm, 35mm, 70mm, and 150mm. I am purposely NOT divulging what aperture these are taken with, except that it is the same one in all 8 images below.
***Note: keep in mind I used a Canon 5D MarkIII which is a full frame body, so if you use a camera that has a smaller sensor (one with a crop factor of 1.5x) the equivalent lenses for you would be approximately: 11mm, 24mm, 50mm, 100mm
This second set of images below was taken with her about 20 feet away from the house. Each time I changed lenses I moved further away from her to keep her relatively the same size in the frame.
Notice in this second set of images how much softer the background is, especially in the one taken with the longest lens? Seeing a correlation yet?! Remember ALL EIGHT images above were taken with the same aperture. The only thing I changed in the first set was the focal length of the lens. The only factor changed for the second set of images was the distance to the background, by having her more several feet forward away from the house.
So what about the aperture?
As mentioned, I purposely did not tell you what aperture was used before you saw the images. Would you be surprised if I said they were ALL taken at f5.6? Well, it is true! All the images above were made with an aperture of f5.6. Not the first aperture you think of when someone says “blurred background” right? Have you got f5.6 on your kit lens? If so, did you think you’d never get those nice creamy backgrounds without investing hundreds, or thousands on a lens with a bigger aperture? Think again, and read on!
One more comparison using f2.8
Just to prove the point here are two more sets of images both taken at f2.8. The first with her close to the house, the second with her further away from the house. Notice how much more the lens and distance affects the blur affect on the background, than does the wider aperture? There is really not all that much difference between this set of images and the very first set at f5.6.
What we can learn from this
While using a wide aperture is a factor in creating a blurred background, it is not the only factor, and in my opinion it is not the most important. If I’m doing a portrait I look for a location where I can place my subjects a good distance away from the background, and I’m usually using an 85mm or longer lens to photograph. There is also a happy medium somewhere between that focal length, and using a lens so long that you have to go across the street to shoot it and end up having to yell just so your subjects can hear you. For that reason a 300mm might be a little excessive for portraits. However, using that 300mm for some wildlife or travel photos you should be able to create some nicely blurred backgrounds, knowing what you know now!
Now, go look at the image at the top of the article again?
It too was at f5.6! Bet you didn’t guess that the first time you looked at it, am I right? Can you tell what else is different in that image? If you know, put it in the comments section below. I’m not going to tell you and see if you can figure it out with the following images, taken in the same location.
Practice and more Reading
I challenge you to go out and do this exercise yourself, don’t believe me. Find a willing subject and starting with them close to a background go through lenses from wide to long, trying different apertures. Then repeat with them moved several feet away from the background. Consider this practice ongoing as well with everything you photograph.
Think about how you can use this new information to create images that more closely resemble the vision of how you saw the scene.
To learn more about the aperture in general and what it does, go read: How to use Depth of Field.
Also related is How to Choose the Right Lens, which talks about what different lenses do optically and when you might choose to use each of them. Knowing what aperture and what lens to use to create just the look you desire, is part of putting it all together. The more you think about these things before you take the image, the better your final images will turn out. I guarantee it!