How is this effect achieved?

[Pie4Weebl]

A guy I work with owns a laser company and I e-mailed him the video asking what the effect was, he responded with this:

"The Effect you are talking about is not an "efect" but is how the camera sees the laser the laser fans are being scanned at apox 30k -50k points per second the darkened waves are just the camera picking up the scan pattern making it seem to have a darkened effect."

Since all cameras work the same it doesn't surprise me that it would show up in multiple videos.
COHERENT LASER ENTERTAINMENT - Flash Intro

 

[Les]

It looks to be an artifact from the Video Camera to me. I don't think you would have seen that standing in the audience.

Ding Ding Ding!!!

And I stand corrected!

 

[chausman]

So if it is just from the video camera, why do we not see it at other times in the video? There are times before and after 2:00 and it doesn't show up.

 

[Pie4Weebl]

So if it is just from the video camera, why do we not see it at other times in the video? There are times before and after 2:00 and it doesn't show up.

This is only conjecture, but my thought is there are certain variables that have to line up for the effect to be seen. I imagine it only works out when the beam is doing a wide enough spread that it can't make it across the full beam in one frame of the camera image.

 

[FatherMurphy]

The answer, if it is camera-related, might be similar to the way that wagon wheels and airplane propellers sometimes seem to reverse themselves in old movies, as the spoke/blade positions change speeds relative to the shutter speed.

 

[skapp]

I've worked in Ohio and PA with TSO and know the laser and pryo guys. I have worked directly with the Pyro Crew Chief Tristan Ford, Pyro Tech Jan Sanderse, and EFX Tech Simon Brierley. The Pyro Company (Pyrotek Special Effects Inc.) and the Laser Company (Laser Design Productions) is owned by the same parent company so I have also spent a good bit of time working around and talking to Laser Crew Chief Jason McEachern.

To clear up the misconception, they do NOT use dryice fog. As a matter of fact what looks like dryice fog isn't fog at all!

The fog often gets a swirl in it from the house HVAC or the fans in the truss that shove the fog downwards. Combine that with the way cameras capture laser you get what is seen in the videos.


In 2009 they used the following on the tour...
Two 10 watt Full Color DPSS/Diode Laser (Center Stage & FOH)
Four 5 watt DPSS KTP NdYag laser
Six LDP 10 Projectors
60 Bounce Mirrors
Pangolin Control Software

2010 was close to that..just more of the 10w full color lasers but I can't find the official list right now.

More info might be available on their website at Laser Design Productions a few of the Gallery images from the 09 tour on their site shows the swirls in the fog as well.