Create a depth of field effect using the new blur filters in Photoshop CS6
If you have the latest Photoshop version CS6, then check out the three new Blur filters (Open the Filter menu at the top and go down to Blur). For depth of field, choose Field Blur.
The first thing to do when the menu opens is to move the pin in the centre (preset with a 15px Radius) over the top of the subject you want to keep in focus. Then reduce its Radius to 0px, which can be done either by using the slider in the top right part of the menu or by dragging the white bar around the pin until blurring disappears.
At the moment your image will be perfectly sharp, but with the main subject set in focus we can begin to work around it. Place multiple pins over the most distant background elements. Place them a couple of inches apart and increase the Radius of each to 30px. This amount can be increased, 30px seems to give a good result.
To help reduce the heavy blurring from the background into foreground, place an array of pins over the subjects in the mid-ground. In this case, we’ve chosen to leave the foremost lion in focus, so have pinned, quite heavily, the surrounding stone structure. Set the Radius for these pins to 15px.
Place additional pins over the main subject and reduce the Radius to 0px for each. If your subject is long then it’s worth placing a pin at the back of it and changing its Radius to 10px to help blend the transition. Try not to go too heavy with the number of pins. Less is certainly more… but concentrate pins around the edges of the subject. You may even to shift the background pins in or out to create a clean edge.
Our image ended up looking like this in the filter…