www.falstad.com/diffraction/
This link takes you to the site of one Paul Falstad to the applet for Fresnel Diffraction. If you select single slit, double slit, etc., you can see a visualization of the different apertures and optical effects. Its really helpful for me to see and be able to manipulate the parameters. I thought it would be interesting and educational to those who are dedicated to the art of pinhole photography. I encourage checking out the other applets that he has on his website, too.
~Liesl
