By Betsy Finn
Bokeh is a Photoshop plug-in by Alien Skin Software that allows photographers to manipulate focus and depth of field. The plug-in simulates the feel of specific lenses, and allows photographers to apply a range of creative focus options, post capture. Prior to experimenting with my own images, I was skeptical about Bokeh's ability to realistically alter depth of field and render creamy highlights. Based on my evaluation of Bokeh, I can say, I'm officially impressed.
While the Bokeh interface is very intuitive, Alien Skin has provided a detailed series of tutorials on how to utilize the plug-in to its fullest potential. After exploring the video tutorials and case studies online, I had a good understanding of how to use Bokeh.
One of the nice things about the Bokeh plug-in is that you can preview the effect in the plug-in's interface before performing the final render. As I previewed a number of Bokeh's Factory Settings, I was impressed at the variety of choices. Some presets were special effect oriented (e.g. Hollow Heart, Lens of Love), and others are meant to approximate a specific lens (e.g. Canon EF 50mm f/1.8 II, Nikkor 105mm f/2.5). In the example below, I chose the Diamond Delight setting, from the series Blur 20% - Bokeh With Highlight Boost.
In addition to factory settings, you can create your own custom modifications by manipulating focus region, aperture controls, and vignettes. The Bokeh plug-in comes with three basic choices of focus region: none, radial, and planar. These options can be used for simple manipulations, or, when used in conjunction with a selection, can create some stunning effects. Available diaphragm shapes include Perfect Circle, Heart of Hearts, and other various shapes with 3 to 11 sides.
The vignette can be applied naturally or based on your focus region, and you can apply color hue to the vignette area as well. Best of all, once you find a customized combination you like, you can save those settings for later use. After exploring my options, I used the radial focus region to draw attention to the main subject, and decreased the Creamy slider setting in the Aperture Controls to highlight the Perfect Circle diaphragm shape. Total time to manipulate this image was about one minute.
Below: Interface, Before and After versions.
Next, I decided to test a more advanced application of the Bokeh plug-in. I wanted to see if I could approximate a shallow and creamy background while keeping the subject in focus. Upon consulting the documentation, I learned that Alien Skin developers made a conscious decision to rely on Photoshop's selection methods rather than replicating the tool within the Bokeh interface. Selecting the subject using Photoshop's quick selection tool was simple and easy. After cleaning up my selection, I opened the Bokeh interface and applied a radial focus region to drop the foreground and background out of focus. Total time on this image was 3-5 minutes.
Below: Interface, Before and After versions.
Finally, I decided to push the Bokeh plug-in to its limit. After refining my selection, I ran the Bokeh plug-in with my selection as the focus region. The background fell off beautifully, and I was able to retain detail in the feather area as well (see selection detail). Total time to manipulate this image was 10-15 minutes, due to the complexity of the selection.
Below: Interface, Before and After versions, side-by-side comparison, detail view.
When using the Bokeh plug-in, I noticed that the rendered areas became too smooth (see grain comparison below); I found it necessary to add grain back into the image after applying the filter. On the Alien Skin forums, I learned developers plan to include a grain feature in the next release of Bokeh.
Below: Original grain (left) compared to post-Bokeh application.
If you're like me, you might wonder whether Photoshop's blur filters can do the same thing. In my opinion, Bokeh's rendering technology results in a superior image (see comparison-Bokeh-Blur - left to right: original, Bokeh, Gaussian Blur). During my comparison test (using the exact same selection), when Gaussian Blur was applied with a large enough radius to approximate the same background blur, the result had a halo effect at the subject/background transition area.
Below: Original, Bokeh, Gaussian Blur.
While Bokeh is no replacement for having good lenses and getting it right in-camera, I can see this plug-in as a practical add-on for Photoshop. Bokeh's versatility allows for a range of practical applications, from manipulating depth of field and adding vignettes to creating special effects by changing diaphragm shapes. What's more, you have your choice of using factory settings, or saving your own presets. If you ever need to drop a distracting background out of focus (after the fact), I see Bokeh being a big timesaver.