Møre Lïtbørd

Last time, I gave the instruction on how to build a lightboard, but not much in terms of how you actually use it. Now I’ve been giving lectures from it (with graduate students as test subjects), I’ve started recording for the undergrad courses, and so I’ve tweaked my setup and learnt a few tricks. This week, I’ll discuss some of them

First, let’s have a global look at the setup:

This is a panorama stitches from 3 or 4 individual pictures since I don’t have a wide-enough lens for to show all of it at once. Let’s have a second look, now with numbered items:

We have (in no particular order) (pay no attention to the misc stuff on the shelves: it’s the basement!):

  1. Computer. A ~10-year old MacBook Pro running Ubuntu 20.04 (Focal Fossa) for Zoom and recording.
  2. Spots. A set of Neewer BiColor 660 LED spots. They are positioned (see diagram below) so that they do not reflect in the class from the point of view of the camera. Two are on the sides and one center, below.
  3. Generic microphone stand reused to hold 3rd spot.
  4. Lectern. I put notes on what to do in what order during lectures or recording. Put at an angle so that it doesn’t show too much I’m reading from it when I write stuff on the board.
  5. Larger screen to show Zoom participants. Higher, the image would reflect on the glass. It sits on a standard milk crate.
  6. Coffee table (from Goodwill). Serves as hub. Not visible: USB 8-port hub, camera battery charger, extra sets of speakers (so that the lightboard doesn’t cut the sound from the laptop). Misc. thingies holder.
  7. Focus pattern to give something the camera to focus on during setup. Might also use “standard test card” (not necessarily the one with the “Indian head”, but maybe this one.
  8. Ceiling light. Should be off.
  9. Bundle of 6′ electrical extensions.
  10. Crop marks. I adjust the view from the camera so that these marks are just barely outside the field of view. It also helps you do stay within field of view.
  11. HDMI to “fake USB Camera” adapter. Used to convert the movie camera HDMI output to the computer as a USB camera (for Zoom). Actually, on the image, it’s the USB cable that leads to the hub with the converter. Also HDMI output to second screen.
  12. A “puzzle play mat”, black and white. That helps if you’re going to stand up all day.

Not shown/not highlighted:

  • Canon HF R800. A basic 1080p video camera with zoom, HDMI output and about 2 hours’ worth of autonomy. It’s uncomplicated, and you can control some of the exposition, frame rate, color balanced. It’s a basic consumer-level thingie, it’s grainy in mid- to low-light, but it works well for hours on end.
  • Canon Rebel T8i (alias EOS 850D, alias EOS Kiss-X10i) for quality recording. It does 4K (that nobody uses, but that may eventually turn out to be useful in post-prod, by shooting in 4K, applying image processing, then downsampling to 1080p), but I use 1080p for now.
  • Good Manfrotto Tripod (maybe different from my model; I had mine for the last 20 years or so).
  • Audiotechnica Lavaliere microphones.
  • A bunch of extensions & power bars:
    • Audio cables with 2.5mm jacks (one going to the camera, the other to the computer).
    • HDMI extensions: one 25′ for the camera, one 6′ for the second screen.
    • At least two power bars: one for the computer and screen, one for the spots.
  • Green masking tape marks. To align stuff. One you’re happy with your setup, use making tape (easy to remove) to mark what goes where.
  • Curtains behind the lightboard but also behind the camera. It keeps the rest of the room from reflecting in the lightboard glass.

The general arrangement is (as seen from above):

The spots are placed to light the screen evenly, but not reflect in it. Two are placed at eye-height (for me, 1m70 / 5’8″ or so) and the center one as low as possible but also as close as possible to the lightboard and you’ll need something else than the default stand that comes with it (it’s a microphone stand).

* *

Finally, you’ll have to experiment. Exposition settings on your camera will vary (because you have a different lens, different brand, etc.). Light will vary. Maybe you’ll find that spots at 50% are good. Maybe you’ll want darker background. Or not.

The markers I use are Expo Neons, but other style works well (liquid chalk works visually well, but isn’t really dry-erasable), some are just really bad (everything that’s vaguely wax-based, like Crayola “dry erase”).

You’ll also have to experiment with sound. Boom mike or Lavaliere? Record sound separately and resync in post-prod or record on the camera itself? I prefer recording on the camera (thus the audio cable extensions).

Finally, the software. I, as a enthusiast penguinisttm, avoid proprietary software. For now, I use Kendlive (KDE application that runs just fine in Gnome). I still have to figure out everything in it.

The rest is up to you.

An example: Des nombres à l’égyptienne.

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