public void setMinDistance(float minDistance) {
        this.minDistance = minDistance;
        if (minDistance > distance) {
            zoomCamera(distance - minDistance);
        }
    }
Sets the min zoom distance of the camera (default is 1)

@param minDistance the desired distance (in world units, default=1)
jme3-core/src/main/java/com/jme3/input/ChaseCamera.java