help with long exposure shot

[polkaisrad!]

http://www.thephotoforum.com/forum/showthread.php?t=34505

ok so this picture right here is a very nice example. Everytime i do this the image of the person fades every time i hit my flash. I usually do it in pitch black (hear it works the best) and use a tripod obviously. Then hold the shutter open and hit the flash for each position. Should I be doing this different?

 

[Big Mike]

If you are doing this with multiple flashes...there has to be no background...otherwise the background will expose through the previous positions with every flash.

The way I would do it, would be to use a digital camera (or scan film) and take multiple photos and use photoshop to combine them. Use one as your base and then add the others as layers in Photoshop. Then erase (or better yet, mask off) everything but the new position...in each layer except the background.

You should be left with one background and a bunch of subjects.

 

[Meysha]

Then hold the shutter open and hit the flash for each position. Should I be doing this different?

Yep that's right. So long as your flash isn't going to be overexposing the background with all these flashes you'll be alright.

I've seen a great example of this with a girl on a swing set and the flash was fired about 5 times during the exposure and she's in 5 different positions. The photo was taken during the dark nighttime, so that the girl was too visible between flashes and didn't blur the photo. And the background was far enough away so that it wasn't overexposed, but it was slightly visible.