How to Blur the Background in Photos: A Quick Introduction
Photographers achieve this look with a combination of the right camera and lens settings. The shot needs to be composed with a proper understanding of the depth of field in mind.
Why Blur Photo Backgrounds?
Whether professional photographers or casual viewers, few people can deny that photos with a subject in sharp focus and a blurred background have a much more professional look than photos with everything being equally focused.
The depth of field necessary to achieve this look in a photo consists of factors such as the aperture, distance, and photo length. Although photographers can add a background blur post-production with software like Photoshop, the effect can look fake if not performed correctly.
Depth of Field Definition
The depth of field, also known as the DOF, is how much of the image is sharp or acceptably focused. Photographers should make it a point to create images with a proper depth of field with the image’s purpose kept in mind.
A shallow depth of field usually looks best for portraits, with the sharpest part of the image being the subject’s face and blurring for the other elements. In the case of landscapes, a larger depth of field with everything being focused usually works better.
When the depth of field is shallower, the subject will stand out from the background much more effectively. One of the most significant advantages for photographers is that undesirable or distracting objects won’t receive as much attention.
By the way, we highly recommend this photography for beginners course to learn the basics such as depth of field and so much more.
Popular In-Camera Methods for Blurring a Background
The methods for creating a photo with a shallow depth of field are easiest to perform in-camera, either by increasing or decreasing distance, using a long focal length, or using a wide aperture.
1. Changing the Distance
Distance is best considered a composition method because it does not involve camera or lens settings.
An increased distance between the subject and background will result in increased background blurring when the subject is further away. The subject should be photographed with a background in the far distance.
When this distance is decreased, the blurring of the background will increase with the subject being closer to the camera. The subject needs to be photographed closer to the background for other elements to be easily visible.
In the case of a group photo, the same principles apply. The objects in the background need to be at a greater distance from the subject group for this effect to work.
2. Keeping the Focal Length Long
The best way to describe the focal length is the distance between the camera sensor and lens when the object is appropriately focused. There are many length options available for lenses, including either a prime lens for fixed focal length and a zoom lens for a variable length.
When a lens has a longer focal length, the result is a more compressed subject with a blurred background and shallow depth of field. A shorter focal length results in most or all elements being focused.
Examples of lenses with short focal lengths include 24mm and 35mm. These lenses are very popular for taking group photos where everyone needs to be in the frame and focused.
3. Increasing the Aperture Width
As a quick refresher, the aperture is the lens’s opening for letting in light. Manufacturers measure this width in f-stops.
Where the depth of field is concerned, the aperture opening’s size makes a difference. Large openings, indicated with small f-stops such as f/2.0, help provide shallow depth of field.
On the other hand, smaller openings, indicated by small f-stops, such as f-16, help create a larger depth of field. When adjusting the settings for proper exposure, remember the impact that the aperture will have on the camera sensor’s amount of light.
Landscapes, architecture, images of vehicles, and similar scenes do best with a narrow aperture of f/8 or f/16, which equally focuses all parts of the picture. Portraits, by contrast, do best with a wider aperture of f/1.2 or f/2.8, which allows for more significant background blurring.
Can These Techniques Be Combined?
One of the most helpful things for photographers to know is that these techniques work well alone and combined. Photographers will often use different techniques together to get the best possible effects.
A typical example of using multiple techniques is in the case of a photographer trying to achieve maximum blurring. For this effect, a photographer may have to have a close camera-to-subject distance, far subject-to-background distance, long focal length, and wide aperture.
All parts of the subject need to be in clear focus for combining techniques like this to work best. There are also post-production techniques to achieve such effects, which we will look at next.
Blurring a Photo’s Background with Post-production Techniques
Photographers sometimes decide to blur a photo background after the fact. In settings where a photographer cannot create a shallow depth of field, post-production options are very helpful.
One of the critical factors with using such a method is making sure the viewer is unaware of the enhancement. When performed correctly, no one will know.
Using Adobe Photoshop to Create Gaussian Blur and Layer MaskS
The image needs to be opened in Photoshop, with a duplicate layer added to use this method. Add a Gaussian blur to the new layer with a fresh layer mask.
Use the brush tool, with black, to paint over the added blur. The edges of the layer mask need to be carefully defined for a more subtle, gradual focus fall-off.
Even though a blurred background might seem like a difficult task when taking a picture, this effect is relatively easy. Solid knowledge of your camera settings and some essential photography techniques will ensure the images come out as expected.
Post-production products like Photoshop also make a difference and may fill in the gaps where photography settings were less optimal. Understanding the different ways you can blur a background in a photo increases your chances of optimal images.