Toronto Photography Meetup Group

Hi everyone,

Seeing the recent adhoc light painting event has made me want to do some of my own. I've been thinking about how I would go about it and the question of a properly lit subject has come to mind.

I'm thinking to do some light painting around a subject and also having that subject properly lit as well. I assume that in a long exposure I would hit the subject with a burst of flash and then proceed with the light painting. My question is what exactly happens here.

If I expose the subject with a burst of flash at the beginning of the exposure does the person remain relatively clear if they don't move? Why is that? Is it because they are illuminated by such a bright source of light? Would the clarity of the subject be compromised if they moved out of the image and you can now see some faint lights in the distance that their body was originally blocking?

Thanks for your help,

Zeekid

This video should explain many of your questions:
http://www.youtube.com/watch?v=4IS-DBZEXcA

As for what happens, you are initially lighting the person, then (I assume by your description) drawing around the person with a light. Because you adding light around the subject, but not blowing out the subject the image of the subject remains. If however you remove the subject and fire the flash again at the same exposure, you'll get a "ghost" of the subject...something like I did here, notice where the two exposure meet at the elbow the skin isn't see-through, while where the forearm is you can see "through" it, especially where it meets the stapler (this was a single exposure with the flash fired twice):


To really understand it though you have to experiment and play.

For instance, here's one that looks like the flash was fired in the middle of the exposure:
http://scienceblogs.com/photosynthesis/K09juggler4866-web.jpg

BTW, I once saw a photographer put 25 separate exposures on one frame of film. It was a picture of a juggler...first he photographed the juggler holding out his hands (but not juggling anything). Then without the juggler he did 24 separate exposures of the ball where the juggler's hands would have been, and the ball in mid-air around where the juggler would have been, by uncovering the lens (while locked in bulb mode) and covering it up again, moving the ball, changing the lighting angle, and uncovering the lens again and again covering up the lens.

You can flash at the beginning or end, it really doesn't matter. It's just easier at the beginning since you don't have to guess so much at relative positions. You can flash the person and then they can do the light painting of a word. You'll get the word and the still of the person.

I'll find the tutorial I saw with a good example later. Got to run to work.

The Example above had the flash at the end. The person held his hand still at the top for most of a long exposure. That way the ambient light was enough to expose the first position. Just before the flash went off at the end of the exposure he slammed his arm down and the flash capture the stapler being hit.

Now if the ambient light was a bit stronger and the exposure a bit shorter we would have started to see some motion blur. This to my mind would have made the shot a lot more interesting.

Let say you want to capture a runner going by. If the exposure without flash is just a motion blur of the runner then with a first curtain (flash at start of exposure) flash the runner would appear to be sharp with the blur in front of him making him look like he's running backwards. In this case you want to use a second curtain flash (flash at the end of exposure) so the blur is behind him.

If you have a strobe then you can stop motion multiple times throughout the exposure for some real interesting effects.