Saturday, March 21, 2009

Video feedback: Rainy day fun

One of the coolest and simplest examples of infinity is the phenomenon observed when two mirrors face each other; each in parallel planes, reflecting the others reflection, as far back into the reflection as we can follow. Hmmm.

If a microphone comes too close to its monitor (the speaker) it squeals. A similar phenomenon can be produced with a video camera and its monitor, but, it squeals visually. We call it video feedback. The most simple examples look very similar the mirror phenomenon. The most controlled can resemble galaxies, cells, or bleeding mandalas of light.

Older TVs and tube cameras give a softer feeling to the feedback than LCD screens and chip cameras. However, old tube cameras can be damaged over time, the same way your eyes might by staring at the sun. Don't worry, if you have a tube camera, you know it because it is probably 30 years old. Along with messing with the focus and exposure on the camera, the tint and color balance etc on the TV itself are another level of control over the effect you get. Older knob control TVs can be changed without the use of a remote, and so no display on the screen during experimentation. That will only be relevant if you or your kid really geeks out, and start clocking serious hours. In that case, wait for garbage day in your neighborhood, go out and pick up a New old TV.  Recycle, Recycle, Recycle. You might even find an old tube camera.

So here's what to do. Plug any camera into a monitor so that if it is pointed at you, then you appear on the monitor. Then, point the camera at the TV and zoom out. You should see a TV inside of a TV inside of a TV ad infinitum. Rotate the camera on its Z Axis, and the ever shrinking TVs will spiral into the distance. Now Zoom in slowly. The images begin to overlap, degenerate, creating patterns. By controlling the light source, ambient light, focus, zoom, exposure etc., Very cool moving images can be produced. 

These photos here were shot off the TV on 2 and 1/4" slides. No computer assisted in the making of these images until they were scanned for publishing here. 

Have fun!

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