  A simple method for presenting a dynamic transition between Fresnel and
Fraunhofer diffraction zones is considered. Experiments are conducted on
different apertures and diffraction patterns are photographed at various
distances between the screen and the aperture. A diverging lens is introduced
into the experimental setup to provide enlarged Fresnel diffraction patterns.
Fresnel and Fraunhofer diffraction patterns and dynamic transition between them
can be easily obtained on a distance of few meters, what gives an opportunity
to use our setup as a lecture experiment. Photographs of transition for square
aperture are shown and discussed.
