How do you record your lectures?

If my lecture is done via a presentation (not my preferred method, but necessary for some classes), I record the audio of my lectures along with a "video" of the slides I use. I use Camtasia to record everything, so the only other thing I need is a microphone.

When I give lectures at the blackboard I don't record them. However, for those lectures I provide a fairly detailed set of course notes.

My preference for teaching undergraduate courses (in physics) is:

• Audio-record the lecture using a small MP3 player hung around my neck, and provide the file to students as a MP3 file
• Write coherent notes on the blackboard that students can use as the basis for their own notes

I specifically do not do the following, which I believe is harmful to students' learning in such courses:

• Provide detailed printed notes
• Use slides (except for occasional complex Figures and animations)

The system my department uses for large lecture classes captures two video feeds: One showing the lecturer and the screen, taken from a camera mounted on the ceiling, the other showing whatever is currently being projected onto the screen, captured on route to the projector. (I normally lecture with a document camera, printer paper, Sharpies, and the occasional small prop.) Audio is captured separately from a microphone on the instructor's lapel.

My department's playback system allows the students to show either or both videos, at adjustable sizes, with synchronized playback, and to slow down or speed up playback. The capturing system automatically locates transitions between slides (or, in my case, new pieces of paper) and provides navigation landmarks for the students.

The system is almost entirely automated. In particular, the lecture videos are not edited at all.

I also provide detailed course notes.