The Field Blur tool

Like all automated tools, the Depth Blur filter will not give you perfect results every time. But there are other tools that you can use to complete the depth-of-field effect. One of the best is Field Blur (Filter > Blur Gallery > Field Blur), which lets you create transitional blur and fall-off. Simply click over the image to add two or more control points, then adjust the circular sliders in each point to control the strength of blur over different parts of the image. Here it lets us blur out the details either side of the subject.