Bowshooter; locked and loaded
Rarely do I get the opportunity to shoot video for scientific research, but from time to time, special projects come up like this particular one. This client had invented an archery product and wanted to test the device to see how it worked under real world conditions. Click on any photo for a larger view. Thank you Brian for taking photos.
Bowshooter with a bounce reflector
The first problem to overcome in seeing the device work is the speed of an arrow. An arrow travels around 300 feet per second or about 204 miles per hour. The delima was, what kind of camera can photograph that kind of speed? The internet and YouTube is littered with beautiful slow motion videos of water splashing, skateboarders jumping and animals running, but none of them approach the speed of an arrow.
Even before I started looking for a camera that can shoot at high frame rates, I knew what the answer was going to be. Vision Research makes an extensive line of high frame rate cameras that do a beautiful job of slowing down motion. Unfortunately they are rare and quite pricey to rent. I then went looking for a cinema camera that can shoot high frame rate.
Sony FS 700
The problem is that cinema cameras have very little need to incorporate high frame rate, so 60 and 120 frames per second is rather standard. I was able to find one camera that can shoot at 240 frames per second in full HD; the Sony FS700.
The FS700 is a beast of a camera, it looks like it was designed by Russian tractor manufacturers because there’s nothing sexy about it. But at about 1/6th the cost of renting a VR Phantom, I wondered if this camera would allow us to see the flight of an arrow? The answer is yes… but poorly
Preparing the bow shooter for firing
The FS700 has a few tricks up its lens that you might not know about in the casual reading of its stats. While 240 fps is it’s stated HD rate, 480 fps is its less-than-HD rate; lets call it SD. But that’s still not a fast enough frame rate to slow down an arrow. The camera has one more setting that allows you to dial in its highest frame rate of 960 fps. At that setting the video comes out looking like bad surveillance video. Apparently, in order to capture this high frame rate, the camera uses only a small portion of its video chip to collect images. The video turns out grainy and somewhat blurry, but it works! It did the job of informing my client about the physics of the arrow as it left the bow.
The team prepares for another test shot
The second big problem we had, was getting a clear shot of the arrow as it left the bow. Due to a previous camera test, we knew there would be no way we could get a shot by placing the camera over a persons shoulder while they were holding the bow. It was determined that we needed a mechanical bow shooter to get the human out-of-the-way so we could narrow our field of view to the arrow as it left the bow. Due to the fact that the bow shooter has components that tend to block the view, it took us hours of trial and error before we were able to line up the camera and bow shooter at just the right height and level to get a fairly clear shot of the arrow leaving the bow.
I figure not long in the future, regular cinema cameras will incorporate higher and better frame rates. Even the Go Pro Hero Three has a stated rate of 240 fps, again at a reduced resolution, so it’s coming. It was a beautiful day and one of the most interesting, challenging and fun shoots I’ve had in a long time. I’m ready to record more of the world in slow motion!