7 steps to get a blurred backgroundmonday 26 October 2015, 21:50 by Iris van Liempt | 1571 times read | 0 comments
By using background blur in your image, you can fully emphasize your subject. It is a commonly used method among photographers, and once you know how to do it, it proves to be not difficult at all. In this article we will be showing you what ways are available to create a blurry background in your images.
In practice it does not usually come down to one of these methods specifically, but rather we want them to work together to create a nicely blurred background. To get the most out of your blurred background, you will need to combine the mentioned techniques.
A blurred background is achieved by using a shallow depth of field. Depth of field refers to the area within your image that is in focus. When you are focusing with your camera, only the point on which you are focusing is truly in focus. In the area in front and behind your subject, the image gets more blurred as you go.
The whole area that is perceived to be in focus by the viewer is referred to as the depth of field of an image. This are can be either very large (almost everything is in focus), very small (almost everything is out of focus) and everything in between. As a photographer, you get to decide how wide the depth of field of your image is. In part with camera settings, in part with the kind of equipment you use and mainly with the choices you make when taking your shot.
1. Large aperture
The best known way to play with your depth of field is probably the use of aperture. The aperture is contained in the lens you use and consists of blades that can open and close. By opening them, more light reaches the sensor, by closing them there is less light reaching the sensor.
There is, however, an extra effect in changing your aperture: it also affects the depth of field of your image. If you set your aperture wide open (large opening, small f-number), the depth of field in your image will decrease.
If you close the aperture (smaller opening, higher f-number), the depth of field in your image will increase. So if you want to create an image with a blurred background then you should use a large aperture opening (small f-number). For example f/1.8 or f/2.8.
2. Fast lens
How low the f-number can go depends on the lens that is mounted on your camera. Every lens has a maximum aperture; the largest opening through which as much light as possible can reach the camera's sensor. This maximum aperture is indicated by a number, usually something between f/1.4 and f/5.6.
The lower the number, the more light can get through the lens. Lenses with a low number are often referred to as 'fast lenses'. In point 1, I already mentioned that you should use as low a number as possible for the maximum blurred background. The faster the lens, the easier to blur your backgrounds.
A disadvantage of fast lenses is that they are usually very expensive. The great exception to this is the 50mm f/1.8 lens (the image below was shot with this lens) that you can buy for around 100 euros for most brands. A definite recommendation if you want to shoot and use blurred backgrounds a lot.
1/60sec, f/3.5, ISO 100 @ 50mm
3. Zoom in
The further you zoom in on your subject, the shallower the depth of field will get. If you have a camera with interchangeable lenses, you can use a zoom lens to create a blurred background.
The focal length of a lens indicates how far you have zoomed in. The higher the number, the more zoomed in you are. From around 100mm (and up), we refer to lenses as tele lenses. For example, a lens with a range up to 200mm is quite a tele lens. When shooting with a 200mm lens, the depth of field will easily become shallow.
1/60s, f/2.8, ISO 100 @ 100mm
4. Close to your subject
The further away your subject is from your camera, the wider the depth of field will be. If you want to have a blurred background, stand close to your subject. In most cases it's better to only have part of your subject on your image. This allows you to get closer and that means your background will be more blurred.
When your subject is, for example, at 10 meters distance from your camera, it will prove to be quite difficult to blur the background. If you're only half a meter away from your subject, this becomes significantly easier.
1/1400s, f/5.6, ISO 100 @ 100mm
Using a compact camera will make it especially difficult to get a blurred background (continue reading to find out why). However, when shooting in macro mode and just a few inches from your subject, even compact cameras will allow you to create a nicely blurred background.
5. Sufficient distance to the background
Above, I mentioned the distance to your subject, but the distance to your background is important as well. When shooting someone with their back against the wall, getting a blurred background will be nearly impossible.
However, if you place this person a few meters in front of the same wall, it becomes a lot easier to blur the wall. The distance between your subject and your background is thus very important in obtaining a blurred background.
This is something to be very alert for, because when you are shooting someone who is posing for you, often they will have a tendency to be close to the background. You will have to tell your model to take a few steps forward; this way your model will get closer to the camera ánd further away from the background.
1/800sec, f/5.6, ISO 100 @ 35mm
6. Bigger sensor
You cannot change your sensor size (except by buying a new camera), but this also affects the depth of field in your image. The bigger the sensor size, the shallower the depth of field.
This effect is especially pronounced in compact cameras or smartphone cameras. With these sensors, usually everything in the image is in focus, because they possess an extremely small sensor. For this reason it is exceptionally difficult with such cameras to work with blurred backgrounds. The only ways you might have to play with a blurred background is by zooming in or by using macro mode.
Foto © door Jim Dicecco
If you enjoy playing with blurred backgrounds, pay attention to this when buying your next camera. Some compact cameras, most system cameras and of course DSLR's possess large sensors.
An APS-C size sensor is just about the minimum size with which you could work if you want to have nicely blurred backgrounds. If you really want to have a shallower depth of field, a full frame camera is ideal (and, unfortunately, expensive). There's also middle- and large format cameras, but these are downright unaffordable in their digital shapes.
7. Image processing
If you are stuck to your compact camera of smartphone camera, you can always use another solution to creating a blurred background: image processing. You can do this using Photoshop, but even Instagram holds a (limited) possibility to blur parts of an image.
But unless you like to spend a lot of time behind the computer, applying step 1 to 6 is the wise thing to do. But even still, image processing can sometimes be a good enough solution.
About the author
Iris started photography in 2012 and found a real passion in photography. She's attending the New York Institute of Photography and studies psychology.
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