In this episode:

History and terminology: Fresnel lenses

Here's a diagram for your enjoyment: http://www.uq.edu.au/_School_Science_Lessons/27.5.1.4.GIF

Industry news:

The New York Times re-instates designer credits

Tech talk: plots

Note: you will notice that my voice changes dramatically about halfway throughout the episode. This is due to my recording most of this show on location at a gig.