Understanding Focus Regions
Once you’ve settled on a preset, click the Bokeh button (just the right of the Settings button). This reveals the blur controls used to modify the chosen preset and create the required focus effect (Figure 4). A few of the settings (such as Blade Curvature) have analogs in Photoshop’s Lens Blur filter, however Bokeh provides a more intuitive workflow. For example, the rollover help text provides descriptions of what each slider does to the photo, rather than providing more a technical description.
Figure 4 The Bokeh controls provide the means for simulating realistic and creative lens blur effects.
Notice the Nikon 50mm preset uses a Bokeh value of 15, and simulates a lens diaphragm with 9 blades, including a rotation value applied the lens diaphragm. These are the settings that will have the biggest impact on your photos.
Bokeh 2 provides three types of “Focus Regions” that you can resize, angle and move around the document: Radial, Planar, and Half. The Radial region (Figure 5) is the default and consists of two concentric circles (which can be stretched into ovals if it suits the composition). The inner (solid) circle defines the boundary within which all pixels maintain their original focus and detail, while the outer (dashed) circle defines the boundary beyond which all pixels become fully blurred, based on current settings.
The distance between these two circles defines the “transition zone” between fully blurred pixels and those that are not blurred. The greater the distance, the subtler the transition will be. This is why you often need “empty space” around the preview, because the bounds of the outer circle (or gradients described next) rarely stay within the frame as you customize the position and shape of the blur.
Figure 5 The Radial option allows you to create a blur around a central subject. The oval as well as the boundary area can be moved and stretched.
The Planar region (Figure 6) works like the Gradient Tool in ACR and Lightroom, and is displayed as three parallel lines. The center (solid) line defines the area where no blurring occurs, while the dashed lines define the location above and below which, all pixels will be blurred fully according to the settings you use. You can move and rotate the “plane” as needed to match the composition, and modify the distance between lines to expand or compress the focus transition zone.
Figure 6 The Planar option works like a Gradient, allowing you to set a focal “plane” along a linear path.
The Half region (Figure 7) gets its name from using half of the Planar focus region, allowing everything below the plane to remain fully in focus. I typically use this type of Focus Region when trying to maintain a realistic look to my landscapes, architectural shots, and family portraits.
Figure 7 The Half option works like Planar except that everything below the plane will remain in focus.
To delete the default Focus Region widget and create a new one, press the Delete key and then click one of the three Focus Region buttons in the Bokeh panel, shown in Figure 8. Note that it is possible to combine multiple focus regions within a shot, though typically only one is required for a basic background blurring workflow.
Figure 8 Click one of the Focus Region buttons to add new regions to your image.