Why Do Photographers Blur the Background of Photos?

Have you ever seen a portrait photo where the background is nice and blurry? That was most definitely a decision the photographer made intentionally, but that brings up the question, why?

Photographers use blur in their images to control the viewer’s focus. A blurry background is often used to draw the viewer’s focus to the photographer’s subject. This is most commonly seen in portrait photography.

There is a lot more to blurry backgrounds in photos than just highlighting the subject of the photo, keep reading as I explain blurry backgrounds and even compare blurry backgrounds from phones and digital cameras.

What Is a Blurred Background Called in Photography?

A blurred background in photography is called “bokeh”. Put simply, bokeh is a visually pleasing out-of-focus or blurred element in an image.

One common mistake in thought that some people have is that the terms “bokeh” and “depth-of-field” are synonymous or even interchangeable. In reality, they are actually the complete opposites of each other.

The difference between bokeh and depth-of-field is this; bokeh refers specifically to out-of-focus elements while depth-of-field refers to in-focus elements. To be precise, depth-of-field is a quantifiable number that represents the distance between the nearest and farthest points that are in focus.

Why Do Photographers Use Blur In Their Images?

Though there are many reasons why a photographer might choose to use background blur in their image, there is one common thread between all of them. Photographers generally use blur to direct the viewer’s focus and help manage their interpretation of the image.

One of the main reasons photographers blur their images is to separate the subject from the background. This ensures the viewer focuses solely on the subject instead of any background or foreground elements. This is why you’ll often see lots of bokeh in portrait photography.

Another reason photographers blur their images is to remove distracting elements from the foreground and background. This goes hand-in-hand with highlighting the subject. If there are distracting lights, signs with words, or other people in the background, photographers might blur them to prevent them from taking focus from the subject.

Blur, or bokeh, is also used to help display depth-of-field. The more background is blurred, the more contrast there is to the in-focus subject. This can be accentuated by shooting with another element in the foreground.

Finally, bokeh is often used for artistic vision; after all, a dreamy bokeh is just satisfying to look at.

Is It More Professional to Blur the Background?

Photos with blurry backgrounds can appear or be interpreted as more professional. The reason for this is because good bokeh is achieved using digital cameras which are used by professional photographers.

Phone cameras use software to isolate the subject, then blur the background. Digital cameras can create bokeh using physics involving the light your camera interprets into images.

The way light is passed through your lens, then interpreted by your camera’s sensor affects the amount of bokeh there is in an image.

To non-photographers, a blurry background can be an indicator of a professional photographer but, contrary to this belief, professional photographers know when to blur a background and when to keep it sharp.

Consider the two photos above, I shot both at the exact same location, but with two key differences. I used a 56mm lens wide open (the lowest aperture) to blur the background in the first shot. I used a 23mm lens at a higher aperture to keep the background and foreground in focus along with my subject in the second shot.

Amateur photographers tend to get excited about blurry backgrounds and shoot every photo with heavy bokeh. There is nothing wrong with this, of course, but it removes the possibility of strategically using the background to provide context to your image, an important part of the composition.

For more information on this critical topic, check out my article breaking down important rules of composition.

How to Blur Background With Your Phone vs Digital Camera

Though it is possible to blur backgrounds with both digital cameras and smartphones, the process by which you do so is completely different for both.

How to Blur the Background of Your Photos Using an iPhone

1. Open your camera app
2. Select portrait mode
3. Tap on your subject’s face to ensure he/she is in focus
4. Take the photo
5. In the “Photos” app, select the photo to view it
6. Tap the “Edit” button in the bottom right corner
7. Tap the “f” in the top left to adjust how much blur there is

How to Blur the Background of Your Photos Using an Android

1. Open your camera app
2. Select “Live Focus”, “Selective Focus”, or “Selfie Focus”
   • These each alternative names for the same function
3. Take the photo
4. View the photo in your gallery
5. Select “Option” to adjust the amount of blur

How to Blur the Background of Your Photos Using a Digital Camera

There are two settings you can adjust with a digital camera to enhance bokeh. These two settings build off each other, and when used together, can create a sharp image with a dreamy bokeh.

The first setting you can change is your focal length. The longer, or tighter your focal length, the more compression your image will have.

Compression simply makes your background appear bigger, now this is a huge oversimplification, but that is the general idea as to why it’s important. Compression will help subdue detail and make your out-of-focus elements appear bigger and more abstract.

The second thing you can adjust is your aperture, a lower (wider) aperture will reduce your depth of field. Recall that depth-of-field is the distance between the closest and furthest point in focus.

Picking the right aperture will allow you to keep only your subject in focus while blurring the background and foreground.

Once you’ve decided what you want in focus using your aperture, you can change the qualities of your bokeh using different focal lengths.

Comparing Background Blur: Phone vs Digital Camera

The key difference between blurring a background with a phone versus a DSLR is that phones use software to blur backgrounds while digital cameras rely on the physics of how light interacts with their sensor to blur backgrounds.

You may have noticed I keep mentioning depth-of-field in this article, that is because it is an extremely important concept to understand when talking about blurry backgrounds. It is also the main differentiator between backgrounds blurred with a phone camera versus a digital camera.

I won’t get into the physics behind why you can control depth-of-field in digital cameras, that’s a topic for another article. The main thing to understand is that, due to the size of the sensor and lens on a smartphone, it is not possible to achieve the same depth-of-field with a phone camera as it is on a digital camera.

To make up for this, smartphones use software to detect the subject, then apply a blur to everything else. The issue with this method is that there is no depth of field. There is no distance between the closest and furthest focus points on display, there is only a sharp subject and a blurry background.

With a digital camera, anything in the same plane of focus as the subject will also be in focus, making the bokeh blend better into the image and creating a natural roll-off in focus.

By understanding this, you can pretty easily tell if a photo was taken on a smartphone’s “portrait mode” or a digital camera. Simply look at the edges of the subject to see if the focus gradually rolls off or if there is a hard jump from sharp to blurry.

This isn’t to say phones aren’t capable of taking great photos, check out my article highlighting why smartphones are great tools for photography.