You will need
- Photoshop and camera RAV
The easiest way to fix the lack of definition of those who use digital SLRs and shoots in RAW format. Open the picture in Adobe Camera RAW (plug-in photoshop for working with images Rav-format) and move the Clarity slider to achieve the desired result. This will give the General appearance of the photo more definition. Do not overdo it, since too increasing this figure, you risk to make a photo rough. Additionally, in the next tab, you can slightly move the slider of "Sharpness". This tool makes it more clear fine details such as hair, iris of eyes, etc. But remember that increasing the sharpness, you can increase the noise. So try to find a balance between these two indicators.
Those who shoots in JPG format, you can use the tools "sharpening" in the menu "Filter" of the program Adobe Photoshop. In this group there are five tools. It is difficult to say which of them you better use it. Try each of them to apply for a new copy of the original layer, and then choose the most attractive to you.
Another way to increase the clarity of the picture is the use of the filter "Color contrast". Create a copy of the original layer and select it. Select the menu item "Filter – Other – Color contrast". Displays filter settings window. Drag the slider to your desired location (I recommend to do several layers with different settings, then to select the best of them). Change the layer blend mode to "Overlay", "Soft light" or "Hard light". Adjust the layer transparency. Your image was not only sharper ,but also more colorful and contrasting.