This is an example of depth-of-field. This photo probably has a wider aperture causing the barb wires to have a shorter depth-of-field, thus the reason for the soft look around the photo. http://photoaffiliates.com/learning-photography-introduction-to-aperture-and-depth-of-field/
HOW APERTURE WORKS: When an object is in focus, light rays originating from that point converge at a point on the camera's sensor. If the light rays hit the sensor at slightly different locations (arriving at a disc instead of a point), then this object will be rendered as out of focus -- and increasingly so depending on how far apart the light rays are. The lens with the larger aperture therefore has a smaller distance range over which objects reaching the sensor will remain in focus.