Video special FX: How to fly around the subject in slow motion like in this Rodney Mullen Video?
Video has certainly come a long way in recent years. Those of us who were old enough were likely wowed when Keanu Reeves ducked under bullets as the camera seemed to wrap around him faster than the bullets were moving.
According to today’s trend trackers, many have been wow’ed again by a beautiful video of legendary skateboarder and entrepreneur Rodney Mullen doing some mind boggling skateboard tricks while the camera zips around him, bending time and smearing his movements into flowing flowering shapes. Some of these camera tricks are nothing new to well-read video enthusiasts, but the casual viewer might find themselves asking, “How the heck are they doing that!?”
Although I wasn’t on set during this production and therefore can’t speak to the specifics of it, read on and I’ll let you in on how this sort of magic is made.
Bullet-Time
The Matrix made famous a video technique called Bullet-Time. Bullet-time is…
a visual effect or visual impression of detaching the time and space of a camera (or viewer) from that of its visible subject.
They accomplished this wrap-around effect by placing many cameras side by side on an arc, pointing them all at the same subject (precision is critical here), and then firing them at, or close to the same time. The Subject (Keanu Reeves in this case) was the center point in a circle of cameras. When these still images are then dropped into video editing software and then watched in succession with each camera’s image lasting roughly one frame, the resulting effect is a camera ‘wrap-around’ that can move the viewer’s perspective quickly around the subject at breakneck speeds, or even freezing the subject all-together as we fly around it. Place a video camera at each end of the arc, and you can be watching a video of the subject and then freeze (or slow) time and fly over to the other camera.
Now imagine, instead of still cameras, we have a series of matching video cameras, all capable of slow motion image capture (high frame-rate capture), and imagine they wrap all the way around the subject and are hidden in the dark so you can’t see the camera arc in the background. The subject is lit from above with one single, controlled light, dropping the rest of the room into darkness and avoiding the capture of lights in the shot.
Now the video editor can fly around the subject and pause on any camera; in slow motion, if he pleases. Mission accomplished…
photo credit: fstoppers.com
But how do they get that cool motion blur effect?
Is it post production magic?
Not likely. This effect is likely done by slowing the camera’s shutter speed down. Think of the shutter as the gate that opens momentarily and allows light to enter the camera and hit its sensor. This typically happens very fast, so that the subject doesn’t have time to move much before the shutter closes. However, leave the shutter open for longer and the subject blurs. If his arms move faster than his legs, then his arms blur more. Set all of the cameras in the arc to a slow shutter speed and do your wrap around and you’ll get to see this motion blur from a moving perspective –pretty cool!
Lastly, how do they accomplish this feat of motion magic?
This one is a post trick. With all of the cameras set back to a fast shutter speed, the videos can be layered over top of each other and offset in time by a fraction of a second. By using a layer effect (“lighten” for those familiar with layer effects) that allows us to see through each video layer where the top layer’s pixels are darker than the pixels of the video layers beneath it, we can accomplish this image doubling/tripling/quadrupling effect that you see here. Think of when you were watching an old movie and it showed the perspective of somebody who was drunk or was losing consciousness –that double/triple image effect was sort of the same thing we are seeing here …only now we have digital layer effects to make the effect a little more pronounced. These layer effects really aren’t anything new, but this is a pretty cool use of them in combination with a Bullet-Time multi-camera setup and one of the greatest skateboarders of all time (Rodney Mullen!).
Now let’s watch Neo dodge some bullets!
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