1. Key Factors:
* Aperture (f-number): This is the *most* important factor. A wider aperture (smaller f-number, like f/1.4, f/1.8, f/2.8, f/4) creates a shallower depth of field, which is what causes the background to blur. Think of it like this: the smaller the f-number, the blurrier the background.
* Focal Length: A longer focal length (e.g., 85mm, 135mm, 200mm) compresses the background and further enhances the blur. Zoom lenses are your friend here.
* Subject Distance: The closer you are to your subject, the shallower the depth of field, and the blurrier the background becomes.
* Background Distance: The *further* the background is from your subject, the more blurred it will appear. Think of a park bench as your subject, and a forest in the far distance as the background.
2. Step-by-Step Guide:
1. Choose a Fast Lens:
* "Fast" refers to a lens with a wide maximum aperture (e.g., f/1.4, f/1.8, f/2.8). These lenses allow more light in, enabling you to use lower ISOs and faster shutter speeds in lower light situations, and most importantly, create that shallow depth of field.
* Popular options for portraits include 50mm f/1.8 (a very affordable entry point), 85mm f/1.8, 85mm f/1.4, and 70-200mm f/2.8 zoom lenses.
2. Set Your Camera to Aperture Priority (Av or A Mode) or Manual Mode (M):
* Aperture Priority (Av or A): This allows you to select the aperture and the camera will automatically choose the shutter speed to achieve proper exposure. It's generally easier for beginners.
* Manual Mode (M): Gives you full control over both aperture and shutter speed. You'll need to adjust both to achieve proper exposure. This offers the most control but requires more experience.
3. Select a Wide Aperture:
* Start with the widest aperture your lens allows (e.g., f/1.8, f/2.8).
* Experiment! Sometimes a slightly narrower aperture (e.g., f/4) might be necessary to ensure your subject's entire face is in focus, especially if you are close to your subject.
4. Position Your Subject:
* Place your subject far away from the background. The greater the distance between the subject and the background, the more blurred the background will be.
* Look for interesting background elements that, when blurred, will create a pleasing bokeh effect (e.g., lights, foliage, textures).
5. Move Closer to Your Subject:
* The closer you are to your subject, the shallower the depth of field. Be mindful of perspective distortion, especially with wider lenses.
6. Zoom In (If Using a Zoom Lens):
* Use a longer focal length (e.g., 85mm, 135mm, or longer) to compress the background and further enhance the blur.
7. Focus Carefully:
* Accurate focus is crucial. Use single-point autofocus and focus on the subject's eyes (the eye closest to the camera).
* Consider using back-button focus. This separates the focus and shutter release functions, giving you more control.
8. Check Your Exposure:
* Ensure your image is properly exposed. If shooting in Aperture Priority mode, the camera will try to select the correct shutter speed.
* If shooting in Manual mode, adjust both aperture and shutter speed until the exposure meter in your camera indicates a balanced exposure. You can also adjust ISO if needed.
9. Take the Shot and Review:
* Take a test shot and review the image on your camera's LCD screen. Check for sharpness on your subject and the level of blur in the background.
* Adjust your settings (aperture, subject distance, background distance) as needed to achieve the desired effect.
3. Additional Tips and Tricks:
* Bokeh Shapes: Some lenses create more pleasing bokeh than others. The shape and smoothness of the bokeh are influenced by the lens's aperture blades. More blades (rounded blades) generally create rounder, smoother bokeh.
* Background Lights: Including small, bright lights in the background (e.g., Christmas lights, streetlights) can create beautiful circular or polygonal bokeh highlights.
* Shooting Wide Open: While using the widest aperture (e.g., f/1.4, f/1.8) can maximize background blur, be aware that it can also result in a very shallow depth of field, making it difficult to keep the entire subject in focus. You might need to stop down slightly (e.g., to f/2.8 or f/4) to ensure sharpness.
* Composition: Don't forget about composition! Blurred backgrounds enhance the subject, but a well-composed photo is still essential. Use the rule of thirds, leading lines, or other compositional techniques to create a visually appealing image.
* Practice: Experiment with different settings and lenses to understand how they affect the depth of field and background blur. The more you practice, the better you'll become at achieving the desired results.
* Post-Processing (Use Sparingly): While the goal is to achieve the blur in-camera, you *can* add a slight amount of blur in post-processing (e.g., using Photoshop or Lightroom) to further enhance the effect, but it's best to rely on good technique first. Overdoing it in post-processing usually looks unnatural.
* Consider Background Choice: Look for backgrounds that have interesting patterns, colors, or textures that will look appealing when blurred. Avoid cluttered or distracting backgrounds that will still be distracting even when blurred.
* Tripod (Situational): In low light conditions, you may need to use a tripod to avoid camera shake, especially when using slower shutter speeds.
Example Settings:
* Subject: Person standing in a park
* Lens: 85mm f/1.8
* Settings: Aperture f/1.8, ISO 100, Shutter Speed 1/250 sec (adjust to achieve proper exposure)
* Focus: On the subject's eyes
* Positioning: Subject a few feet away from you, with trees in the background several feet behind the subject.
In summary, creating blurred backgrounds in portrait photography requires a combination of understanding key factors like aperture, focal length, subject distance, and background distance, and then applying those principles in practice with careful attention to focusing and exposure.