View Full Version : Person walking @ normal speed, crowd walking at mach10 speed??


snafu005
October 20th, 2002, 09:52 PM
I was wondering how I can have a video of 1 person walking at normal speed, but have EVERYONE else even the cars at warp speed? Having the subject walk REALLY slowly while filming.. is this the only way?

and what is the best way to have a blur sort of effect behind the mach 10 sped up crowd?

TIA:-)

Adrian Douglas
October 20th, 2002, 10:01 PM
There's a number of way you can do this but the one I like the is to shoot the first shot of the person walking at normal speed. Then shoot the same scene again without the walker but with the cars and other people. Shoot the second scene at a slow shutter speed, like 1/12 (or 1/15 for NTSC). You'll have to adjust your F-stop to maintain constant exposure between the two shots.

In post lay your walker clip on the timeline as it is. Create a track ABOVE this one and lay the blurred clip down at 50% transperency (You may have to change this to suit your clips).

The effect produced is a dreamy kinda look that looks best if the walker is in slo-mo.

snafu005
October 20th, 2002, 10:21 PM
hmmm
if I do it your way the person walking would look sort of ghost like correct?

thanks for the suggestion, I think I'd rather go for a non ghost like look hehe

:-)

Henrik Bengtsson
October 21st, 2002, 03:04 AM
The double exposure version also only works with a fixed camera unless you have a very expensive motion control rig for the camera.

To have people interact (ie. avoid) the person you are filming you can either use a dummy (so they have to avoid something ) and shoot the subject against a bluescreen (still, fixed camera or you have to use a MCR or some hardcore tracking :)

But still, at the end of the day, the easiest way is to tell the person to move very slowly. (Orbital music video comes into mind)

/Henrik

Bill Ravens
October 21st, 2002, 07:20 AM
Actually, this is very easy to do with Vegas Video. As described, produce two clips, one with the person walking slowly, another of the frenetic people walking. It would help a great deal to have the single person walk while having a green screen following behind him, however, this may not be possible. At worst, this person should walk in front of a continuous, non mottled background. By chroma-keying this person and using composite tracks, the slow person can be overlayed on the fast moving crowd.

Henrik Bengtsson
October 21st, 2002, 08:27 AM
If you do not track the two camera movements (or hide the feet of the walking person) very carefully you will end up with a sliding mooonwalk effect on the foreground walking layer. Only way to avoid this (as i mentioned earlier) is either to have a fixed camera, a expensive motion controlled rig or by tracking the camera movement very carefully.

/Henrik

Bill Ravens
October 21st, 2002, 08:50 AM
ahhh, indeed.....unless you don't pan the cameras. IE, frame the shot such that the FOV is wide enough to not pan.

snafu005
October 21st, 2002, 09:56 PM
thanks for all the input guys!!! I will let u all know how it turns out!! =-)