Photoshop lets you easily select the areas/pixels of an image that are in focus.
Do the following:
- With the image open in Photoshop, choose Select > Focus Area. In the Focus Area dialog box, you can make changes to the default selection.
- Adjust the In-Focus Range parameter to broaden or narrow down the selection. If you move the slider to 0, the entire image gets selected. However, if you move the slider to the extreme right, only the parts of the image in clearest focus remain selected.