Best Answer Photographa , 21 December 2013 - 03:52 PM
Painting with light basically describes the process of using a long shutter speed and controlled lighting to create artistic blur.
When the camera shutter is open, the sensor on your camera collects light. When it's dark, the shutter can stay open for longer so that it can collect more light from the environment and produce a brighter, more detailed photo.
If you're in a dark street, you can set the camera on something stable (a tripod works best) and take a photo of a subject with a light source using a slow shutter (the shutter will stay open for longer), and if the subject moves the light source (a flashlight or sparkler works well), the light source will appear to blur (it'll look like a line of light in the photo).
For creative light-painting photos, you'll want a shutter that can stay open at least 3-5 seconds (if you want a group to write or draw something). You can go above or below this as you wish. When you've found a good shutter speed that works for whatever you're trying to draw, you can adjust your aperture and ISO to allow your photo to be decently exposed.
I'd recommend an ISO of 200 - 400 for light painting photographs. This will reduce noise in the photo and can give you enough brightness.
Your aperture will vary based on how bright your scene is and how long you want to keep the shutter open. A constricted aperture will allow your shutter to be open for longer periods of time (and in brighter areas), but if you want a quick drawing with a faster shutter, or if you're in a darker area, you can open up the aperture a bit.
Anything that light shines on will show up in your photo. If you have something backlit in the background (such as city lights) and a person who isn't lit walks in front of the lights and then steps away the photo will seem as if the person never walked there. If you have a group of people with flashlights pointed in the direction of the camera, and if they're not lit up, they won't be visible in the photo, but the flashlight light will be.
If you'd like to have your light artists visible in your photo, but you don't want them blurred, you can keep them as dark as possible (and moving quickly if there's light in the background), and you can fire a quick flash at the end of your shot to expose them without blurring them. (Background lights will also be visible well if you do this.)
Play around with it and see what you can do!
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