Sometimes we want to intentionally blur the background. It can be a mistake to think we always want everything in sharp focus in our picture.
A blurry background can visually separate the subject from distracting things in the background of your picture. That makes a better photograph.
There are two ways to do this when taking pictures.
First, you can get a blurry background by selectively controlling focus.
Having a small range of things in focus can create a sharp subject and a blurry background. This is called a narrow depth of field.
Secondly, you can blur the background by using motion blur to get a blurry background while keeping a sharp and clear subject.
Additionally there are also many ways to do this after you take your photo with photo editing software. This digital photos tips article will discuss a few of these techniques.
If you use Camera Settings that give you a small depth of field, your subject will be sharp and your background will be blurry.
For a detailed explanation of controlling depth of field, go to What-is-depth-of-field?
I shot this photo of the red car sitting on top of my tripod using a large aperture of f-4 with my Canon camera and 24-105 zoom lens.
You can see the edge of a big TV screen in the background it's very blurry. There is a second reason the background is extremely blurry. The car is very close to the camera. The background is relatively much farther away from the subject.
With this picture of my model leaning against the fence, I was able to blur the background by using a wide-open aperture of f2.8.
This is a great tip to use when doing portraits.
This is another Common Photo Mistake that photographers make.
When they want the background to be blurry, they don't put enough distance between the subject and the background.
One fairly easy way to create motion blur in the background is to take your picture while following a moving subject.
The idea is that your subject is fairly sharp but the background is blurred to show motion.
This is called panning and you see it a lot in motor sports and sometimes in wildlife photography.
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In this photo of the white race car, the camera tracked the direction of the car as the shutter button was pressed.
You can see how the background (and the foreground) are not sharp.
Because the car stayed in the same spot of the camera's viewfinder while the picture was being taken, it remained sharp even though the camera was moving.
I had some fun one day experimenting with different shutter speeds and a bike rider. It was interesting to see how much of a blurry background I got with each shutter speed.
Playing around like this, creating your own little photography assignments is a great way to improve your photography, not only on how to blur the background, but with any aspect of photography you wish to understand better.
Gaussian Blur is another way to blur the background and it's done with digital retouching. In this basketball photo, I used a "filter" in the editing software program Adobe Photoshop called Gaussian Blur.
Sometimes it is difficult to separate your subject from the background when you take the photo, so you must do some photo retouching.
I wanted to blur the spectators in the stands in the background.
Here is the technical stuff. To have the most control, in Photoshop you create an exact duplicate copy of the image, called a "layer." You then add a "layer mask" to this new duplicate layer.
This gives you the ability to make any changes you want to this new duplicate layer mask while still preserving your original picture untouched.
You can then "reveal" some areas of the changed duplicate layer mask as much as you want to. In the top photo, the spectators are somewhat blurred because I used a large camera aperture and got a small depth of field. I wanted to blur the background a bit more.
If you look closely at the same photo underneath the top photo, you'll see that the spectators are a bit more blurred, but it still looks completely natural. This is a good use of Gaussian Blur.
Radial Blur spreads out in a radial direction, similar to spokes coming out from the center of a wagon wheel or like the colored streaks coming out from a fireworks explosion.
In Adobe Photoshop, you can add a radial blur to the background or the subject or both.
In this basketball photo I created a radial blur, centered behind the basketball. This really creates the feeling of motion toward the ball.
I then "hid" the blurred basketball in the blurred duplicate layer mask, so that it remains sharp in the final photograph.
These are just a few examples when you may want to blur the background on purpose. Remember to have an attitude of curiosity when trying new techniques with your photography. Most of all, have fun learning how to take better pictures.
Blurry Pictures. More information on this topic, and samples on shutter speeds and motion blur.