I have an admission to make. I didn’t buy a DSLR to just capture my kids’ smiles. Point-and-shoot cameras accomplished that task sufficiently. While I didn’t understand exactly what made a DSLR camera better than a point-and-shoot, I did know the photos were better.
Because they had a blurry background.
That’s right. I wanted a DSLR camera to get blurry backgrounds. For me, that is what the difference between a “professional photo” and a snapshot.
And I know that I am not alone! Maybe you have seen those photos on Instagram and on holiday cards and wanted to be able get that gorgeous blur. Perhaps like me you invested in a brand new camera so that you could take those kinds of pictures.
One of the first lessons I learned in my pursuit of blur is that the camera isn’t what is going to make the difference. It’s how the photographer uses the camera, lenses, and all of the settings.
And it’s not always easy. Sometimes you get that blur you are after but your subject is also blurry! And that’s definitely not what we want.
To get the results you want, you first have to understand depth of field and the focal plane and what variables will affect them both. And I am here to help! Let’s work together to decode the vocabulary and fully understand how to get that blurry background. And then you can go out and get photos you will love (blurry background and all).
What is a focal plane?
The focal plane is the area in your photograph where your subjects will be in the sharpest focus. Picture it as a thin imaginary window pane that reaches from left to right across your photo. When you choose a focus point while taking a picture, that is where your focal plane will land. Anything along that imaginary plane will be in sharpest focus.
You will want to keep the focal plane in mind when positioning multiple subjects and when choosing your focal point in-camera. I always like to focus on the inside corner of an eye for portraits as that his the most important feature to have nice and sharp.
What is the depth of field?
The depth of field is the area surrounding your focal plane where your subject still appear acceptably sharp. The smaller your depth of field, the more blurry your background (and foreground) will be. The larger your depth of field, the more the area around your subject will be in focus.
For large groups of people, you will want a larger depth of field so that everyone is in focus. In landscape shots, you usually want an even larger depth of field. You want to get everything in focus over a great distance. For portraits of single subjects, you might want a narrower depth of field. This keeps everything else blurry and draws the focus right to your subject.
You can adjust the depth of field by choosing the appropriate aperture.
What affects depth of field?
There are three main variables that will affect your depth of field (and your ability to get blurry backgrounds). Aperture, distance, and focal length. Understanding how these three variables work is the key to getting blurry backgrounds in your photos.
Aperture, also known as the f-stop, is the hole within the lens that allows light to travel into the camera. You can adjust the aperture and make that hole larger or smaller. This will let more or less light into the camera as well as making the depth of field deeper or shallower.
The larger the aperture (and the smaller the f-stop number), the more shallow the depth of field. The smaller the aperture (and the larger the f-stop number), the more broad the depth of field.
Every lens has a top and bottom limit on how small or large the aperture can be. Look up the specifications of your lens to know the limits.
It is important to note that changing your aperture will also effect the exposure of your image. As such, you will need to make adjustments with your shutter speed and/or ISO to accommodate the changes in your aperture.
Distance between the camera, subject, and background is another important factor that will affect the depth of field and blur. The closer you are to the subject, the thinner the depth of field will at any given aperture. The further your subject is away from the background the more blur you are going to be able to get at any given aperture.
I really wanted to take a picture of the princesses with my aperture set to f/1.4. However, because they were on different focal planes and my depth of field was so shallow, they were out of focus.
I was able to move back a few feet and take the picture with my aperture at f/1.4 and they were in focus! I cropped the picture to make the princesses appear that I was closer than I was but you can see how just creating distance will make the depth of field deeper.
Similarly, if you want a background to appear blurrier, try moving your subject further away from it. This will allow you to use the camera settings you already have dialed-in while changing what will be in focus in your photograph.
The focal length of a lens is how “zoomed in” your images are. It determines how much of a scene the camera can see. The higher the number, the more zoomed in picture will look.
There are two types of lenses. A prime lens has a fixed focal length. A zoom lens that will cover a range of focal lengths. The aperture on a zoom lens may change as you change the focal length. Or your zoom lens could be a fixed aperture zoom that will stay at the same aperture throughout the range of focal lengths. Be sure to check the specifications of your gear.
The longer the focal length, the narrower the depth of field at any given aperture. The shorter the focal length, the broader the depth of field will be at any given aperture. Telephoto lenses will give you a lot of blur at a given aperture while wide angle lenses will have more in focus at the same aperture.
All of these examples are taken with prime lenses: 35mm, 50mm, 85mm and a 100mm. I kept my aperture at f/2.8 in every shot. I also kept the camera in the same spot for each shot so you can compare the different focal lengths easily.
The BEST way to understand depth of field, focal plane, and how to get that beautiful blur (the pros call it “bokeh”) is to practice. Your set up doesn’t need to be fancy! Just grab a couple toys and practice changing the aperture, distance, and focal length. The more you try new things in a controlled setting like this, the easier it will be to choose your settings when the kids are doing something adorable in front of the camera.
You have everything you need to get that gorgeous blur in your own photographs. So let’s go out and capture it!