A blurred background is a popular photographic and video technique that separates a subject from its environment. This effect focuses the viewer’s attention on the subject while softening the background details. But what exactly is this called? The blurred background goes by several common names that describe the visual effect.
Depth of Field
Depth of field refers to the area in an image that appears sharp. The rest of the image outside that area appears blurry. With a shallow depth of field, only a small portion of the photo is in focus. This creates a blurred background behind a crisply focused subject.
Depth of field depends on several camera settings:
- Aperture – Wider apertures (small f-stop numbers) decrease depth of field
- Focal length – Longer focal lengths decrease depth of field
- Distance to subject – Closer focus distances decrease depth of field
So adjusting these settings is key to controlling the depth of field and background blur.
Bokeh
Bokeh describes the visual quality of the background blur. It comes from the Japanese word “boke” meaning haze or blur. Photographers use bokeh to refer to the pleasing, artistic quality of out-of-focus areas in a photo.
Bokeh is affected by various factors:
- Aperture shape – Rounded aperture blades produce smoother bokeh
- Lens aberrations – Spherical/chromatic aberrations affect bokeh
- Size of background objects – Larger blur circles tend to be softer
Pleasant, smooth bokeh is widely desired in photography. It distinguishes an image from a simply out-of-focus background.
Portrait Mode
Portrait mode is a setting on smartphones and digital cameras designed to create background blur. Other names manufacturers use include Live Focus, Portrait Lighting, or Aperture Effect.
Portrait mode uses various methods to mimic shallow depth of field:
- Software algorithms – Separate subject from background digitally
- Dual lenses – A main and telephoto lens create a depth map
- Computational photography – Uses machine learning for depth sensing
Portrait mode makes it easy to get background blur without adjusting camera settings manually. It’s optimized for portraits but also works on other subjects like pets, food, and flowers.
Lens Compression
Lens compression is an optical effect that also enhances background blur. It’s created by using a longer focal length from a greater distance.
Compression has two main effects:
- Flattens the apparent distance between foreground and background
- Enlarges background objects relative to the subject
This magnifies any blurriness in the background. Compression is useful for portraits when you want an even more blurred background.
Factors Affecting Background Blur
Many camera settings and shooting techniques can adjust the look of background blur. The primary factors are:
| Factor | Effect on Background Blur |
|---|---|
| Aperture | Wider aperture increases background blur |
| Focal length | Longer focal length increases background blur |
| Distance to subject | Closer distance increases background blur |
| Distance to background | Farther background increases blur |
Understanding these factors allows full control over the look of the blur. Photographers manipulate depth of field creatively for different artistic effects.
Achieving Background Blur
Here are some tips for achieving a blurred background in your photos:
- Use wider apertures like f/2.8 or lower
- Get close to your subject and distance from the background
- Minimize depth of field by using longer focal lengths
- Throw the background out of focus by selective focus techniques
- Use portrait mode/computational effects on smartphones or cameras
With practice, you can learn to control the amount of background blur. This directs the viewer’s eye to key parts of the image and isolates the subject.
Creative Uses of Background Blur
Background blur serves many useful purposes in photography:
- Simplifies composition – Removes distracting or cluttered backgrounds
- Separates subject – Defines the subject against an indistinct background
- Directs focus – Leads the viewer’s eye to the subject
- Provides context – Can suggest a scene while keeping details soft
- Improves lighting – Soften or diffuse harsh backlights and shadows
With creative lens choice and positioning, the possibilities are endless. Background blur gives photos a professional, artistic quality.
Background Blur in Video
Cinematographers also use background blur to similar effect in films and videos. Selective focus isolates characters against blurred backgrounds.
Videos use various techniques to create background blur:
- Shallow depth of field – Wide apertures, close focus distances
- Larger sensors – Like full-frame give shallower depth of field
- Telephoto lenses – Compress the scene and magnify blur
- Post-production effects – Like Gaussian blur added in editing
This cinematic blur effect has become popular for interviews, films, and documentaries. It guides the viewer’s attention during movement and action.
Examples of Background Blur
Here are some common examples where you see background blur used effectively:
- Portraits – Blurs the background to emphasize faces
- Abstract – Blends and obscures shapes and colors
- Landscapes – Blends foreground and background layers
- Sports/Motion – Conveys movement and speed dynamically
- Macro – Isolates tiny details against an indistinct background
Artistic use of background blur defines many classic photos and cinema shots.
Controlling Background Blur
To control background blur effectively, the key steps are:
- Choose a wide aperture, usually around f/2.8 or wider
- Position the subject close to the camera
- Increase distance between subject and background
- Use a longer focal length like a telephoto lens
- Focus precisely on the desired subject
- Use portrait mode/computational effects if available
With practice, photographers gain an intuition for setting up shots with just the right background blur. It takes experimentation with lenses, distance, and composition.
Editing Background Blur
Photo and video editing tools provide additional options for enhancing background blurs.
- Gaussian/lens blur effects – Increase existing background blur
- Masking – Separate subject from background for selective editing
- Blur brushes – Manually paint blur onto specific areas
- Filters – Blend and obscure background details more
Used with care, editing can supplement optical background blur. But optimal blur comes directly in-camera.
Background Blur vs. Deep Focus
Background blur is just one approach to image composition. Its opposite is deep focus where both foreground and background are sharp.
Deep focus is created through narrower apertures (higher f-stop number) and wider depth of field. This keeps more of the image in focus.
Each technique has advantages:
| Background Blur | Deep Focus | |
|---|---|---|
| Effect | Subject isolated against blurred background | Entire image sharp from front to back |
| Use | Portraits, selective focus, creamy bokeh | Landscapes, architectural shots, deep space |
| Challenging for | Moving subjects, action | Small sensors, low light situations |
Skilled photographers select the approach according to their creative goals for the shot.
Conclusion
Background blur goes by many names, but all refer to artistically throwing the background out of focus. Photographers control it using wide apertures, close focus distances, and long lenses to direct attention on subjects. When used effectively, background blur lends images a professional, visually pleasing look. This popular photographic technique continues to be a vital creative tool for both still and moving pictures.