Top picture: Floor lamp sliding back and forth; long exposure photography done right!
Bottom picture: Bug sweeper waved back and forth reveals microphone's capacity to eavesdrop. Loudspeaker emits a test tone, and a lock-in receiver picks up even the weakest of signal transmissions and outputs to an attached SWIM (Sequential Wave Imprinting Machine) that displays audio "metasensing" waveforms.
In this Instructable I present 8 simple steps you can use to mimic human vision and capture a true and accurate picture of a light source that is being waved back and forth.
The result is a sequence of exposures that can be combined (9th step) into a single .gif image that shows the back and forth motion nicely.
This is the sequence of steps I've developed over that past 42 years (originally back in the days of film, to make "flip books" of pictures that show light trails in long exposures of a linear array lights I made to see radio waves, sound waves, etc.).
Once you get the hang of it, it is quite quick and simple to do.
This method can then be applied to phenomenal augmented reality as in my previous Instructables.
Begin with a light source such as the augmented reality wand you made from one of my previous Instructables, or simply a light bulb or candle or anything else that glows.
For best results, use a camera with manual exposure settings.
A camera flash helps fill in the details, and you get a nice "flash and blur" effect. The following steps assume you have the more common first-curtain flash sync (you can easily adapt to second curtain sync if that is what you prefer).
Locate a dark space where the lights can be turned off. Here we are using a light bulb in a dark classroom. Choose a dark black background ("blackground") for best results. Here the blackground is the blackboard. It can also be a large open dark space, or you can hang a "blackdrop" (e.g. a black backdrop cloth)....
Identify a beginpoint and an endpoint. Mark these with objects that the subject can easily see in the dark (e.g. see by only the light of the lamp), or by objects the subject can feel. Here we use the two ends of a chalkboard that the subject can feel by running his fingers along the chalk trough, in this example.
Here a camera on a tripod is set to "B" ("Bulb") and a remote control is used to activate it so as not to shake the camera: remote activation means we can actuate the shutter without pressing on any of its buttons which would shake it and perhaps make the exposures blurry or misaligned.
Before you turn off the lights to "Begin", you might want to take one or more pictures with the lights still on, and then turn the lights off and take one or more pictures of the dark (no flash) to characterize the ambient light in the scene. You can use these for advanced image processing (e.g. to model the background statistics of the light in the room, analogous to a "room tone" audio recording). I call these a1.jpg, a2.jpg, a3.jpg, ... ("Ambients").
Have the subject stand at the beginning position holding a light source. Here the subject is holding a light bulb plugged into a light dimmer and turned down really low. I like to use a reasonable size light bulb like a 750 watt, 1000 watt, or 1500 watt light bulb dimmed down to a really low brightness, so we can see the intricate details of a nicely sized bulb and nicely sized filament.
While the subject stands still, take a picture of the subject holding the light.
Sometimes I take multiple "Begins" and assign them filenames like b1.jpg, b2.jpg, b3.jpg and pick the best one, or use more than one if you want your exposure .gif file to ultimately "dwell" at the beginpoint for longer.