There’s nothing better than a blurry background in a photograph. When a photo has something clear and crisp in the foreground against a blurry background the object in focus stands out more and draws the eye. It is best for photos when you want to see something in great detail or something really small.
When it comes to the background blur there are four things that you need to remember; distance from the subject, aperture, focal length and sensor size. The closer you are to the subject of the photograph the better the background blur will be. The aperture controls the amount of light that gets to the camera sensor. The smaller the aperture the better the blur. The focal length refers to the cameras zoom and angle of view. A long focal length will blur your background. A camera with a small sensor has a large focal length and a longer focal length provides a blurred background.
Good blur quality is called Bokeh and it refers to backgrounds that create rounded, soft lights. You can typically see this when there is foliage in the background. Good bokeh enhances the subject while bad bokeh is a distracting blur. Some photographers even use it artistically using the blurry lights with a dark background.
Depth of Field
A camera’s depth of field refers to the length between the object nearest to the camera and the ones furthest away that appear in focus. As a result, the areas in the image that fall outside of the depth of field will be blurry. A shallow depth of field is achieved with a wide aperture and either standing close to or zooming in on the subject, this will achieve that blurry background that you are looking for. Shallow depths of field are best achieved with cameras that have a macro setting.
This setting will preselect a faster shutter speed along with a wide aperture to achieve the blurred background. When you select this setting turn off your flash, get close to the subject or zoom in and this will give you the best effect. Since you don’t use the flash with this setting make sure that there is enough light available for your photograph.
Aperture Priority Mode
This pre-set is semi-automatic and it is available on most cameras. Once you set your camera’s f-value the camera will automatically chose the matching shutter speed and ISO-setting. Similarly, you can get this effect by using the smallest f-stop possible.
Cell Phones and Point-and-Shoots
Even when using a camera with less functionality you can achieve a small amount of blur. If the device has an image destabilisation setting, switch that on. Keep in mind that this setting creates more of a motion blur vs a traditional blur. If you do not have this setting then go to portrait mode, turn off your flash, make sure the subject is far from the background and move in close or zoom.
If your photograph did not come out the way you wanted it too you can still edit the background to your liking in post. There is the Simulated Bokeh effect to add rounded lights, the Gaussian Blur for a soft and even blur and the Unsharp Mask that applies a circle like blur around the subject.
A camera can only zoom so much so if you want to achieve an extreme zoom with an extreme blur for the background you will need to get a lens that enhances these functions. The best lens to achieve this is the DSLR lens.