I am using blender 2.79 and the depth of field works in preview just fine but when I render it doesn't show the blur. I've checked most the setting I know about for depth of field. Shading is set to depth of field the f-stop is set at 0.5 Object is selected (a Barrel). I am using Blender Render Not Cycle Render. I have tried using nodes and i get the same results.