Reply #2: i went to a photography workshop this weekend

[rdking647]

this was one of the techniques we covered.
basically what you do is set the camera on a tripod.. stop the lens down as far as you can.. then take the shot as people walk either away from or toward the camera .if the exposure is long enough (these were in the range of 1-6 seconds) the people will look likes ghosts. you have to experiment because the faster the people walk the more ghost like they look