Real focus happens inside the camera's lens element. The sharpening features in Photoshop  CS3 exaggerate the contrast along edges in a photograph to transform a well-focused image  into an outstanding image. In Photoshop CS3 Sharpening Images, Deke McClelland teaches a  host of sharpening and noise reduction techniques, including using filters such as  Unsharp Mask, Smart Sharpen, High Pass, and Reduce Noise. The training teaches the  essentials of sharpening, including what it does, why it's important, and how the filters  function. Plus, the training covers Deke's recommended best practices, including the four  distinct varieties of sharpening, which can be used independently or in combination with  each other.