In the first part of my two-part look at understanding bokeh, I discussed some of the basic science and art behind out-of-focus photographic blur. But to fully understand bokeh, it's also important to look at its relative opposite — sharpness.
As you might expect, there will be differing views on exactly what constitutes sharpness in a digital image. A portion within a photo that is sharp enough for you may strike me as a bit soft, or vice-versa. So, how do viewers of images decide exactly where something comes into (or goes out…
via Imaging Resource News Page http://www.imaging-resource.com/news/2013/09/20/understanding-bokeh-the-art-and-science-behind-the-beauty-of-blur-part-2