What is the highest aperture on a DSLR camera?

high aperture

While many lenses have a maximum aperture of f/22, some lenses have apertures that go to f/40 or higher! Generally, photographers do not use any aperture above f/18 or f/22 because of diffraction.  Diffraction is a phenomenon which causes a loss in sharpness because light rays are bent around the aperture. The following is a CONTINUE