This is a video I made with a student some years ago, one of the early projects that helped get me hooked doing videos. Anyway, it shows a polished piece of steel being pulled in tension. The Lüders bands are simply bands in the metal where permanent, plastic deformation begins. The point made to students that only parts of the sample "yield" at a time.
Lighting is provided by a ring illuminator and the microscope is Wild-Heerburg stereo microscope. No narration was included in this because I meant to leave this to the instructor.