You can change Camera settings in the bottom left panel of Skin Renderer, this will allow you to change Depth of Field and Focal Length.
Depth of Field
The Depth of Field controls blur in the background of your render. To move the DoF, go into the Camera Tab in the Objects panel, and show the "Focal Point" object. This will make a point in the 3D Viewport which you can move, and the camera will focus to wherever this is.
Change the Aperture Size to control the intensity of the Blur, with higher values resulting in a more intense DoF effect. Other settings aren't important, unless you know real Camera configurations.
Below is an example comparing values 0 to 0.3.
The Focal Length allows you to control the physical depth of the render. Change the value of Focal Length to adjust this feature.
Below is an example comparing values 40 to 25.