Example:
This photo was taken with a 35mm lens at an aperature of f/2 at pretty close to it's minimum focus distance notice how small an area is actually in focus, the stuff behind the side marker was only about 2 feet away if that much:
This one is pretty close to minimum focus distance as well (same lens), just a much smaller aperture (iirc it was around f/22). Notice how much longer things stay in focus
