Whether you're working with photos you've taken yourself or have purchased from a stock image supplier, rare is the shot that can't benefit from some degree of sharpening, whether to the overall image or to selected areas. And beyond just making it look its best, certain parts of the image may be candidates for some creative application of sharpness or blur to enhance the mood or lead the viewer's eye to the desired focus of interest.
Photoshop, of course, provides an array of sharpening techniques, to the degree that entire books have been devoted to the topic, such as Real World Image Sharpening (Peachpit Press). But where there's complexity there are always plugins or dedicated applications standing by. In this case plugins such as Nik Software's Sharpener Pro, Topaz InFocus and The Plugin Site's FocalBlade are mature products that provide robust sharpening functionality.
Veteran plugin developer AKVIS has contributed Refocus, which places an emphasis on ease of use and works in Refocus, Tilt-Shift or Iris Blur modes. The plugin/application allows users to sharpen or blur entire images, as well as selected areas, by choosing a preset or manually determining parameters. Specifying the areas to be sharpened or blurred is accomplished by simply drawing lines directly on the image.
With version 3 users can add bokeh and lens blur effects to their photos. Image View Modes provide a range of options for displaying the original and processed images, with Before and After states. This version also adds improved RAW processing, with support for images from Canon cameras (CR2): Canon EOS 6D, Canon EOS 600D, Canon EOS 1100D, Canon PowerShot S100.
The Business version of AKVIS Refocus for Mac and Windows, which includes the plugin and applications and can be used for commercial work, can be purchased on the AKVIS site for $72. A trial version is also available for download.