Frequency of the bass strings and high shutter speed of the camera lead to this suprising string-wobble footage.
There is no slow-mo applied to the take. Sound is original.
Video was filmed with a Canon 5D Mark II, Nikon 50mm lens on 1,8f.
There has been some discussion about what we are actually seeing here—whether it’s due to a strobe effect between the shutter speed and the string vibration, or it’s caused by the rolling shutter of the camera itself.
It’s both, to an extent. There are some other tests out there (1, 2), and notice at the end of the second clip, when the string is almost horizontal, the chaotic wobble is nearly gone. A cool effect of the rolling shutter.
You may have seen the rolling shutter effect in a video like this involving an airplane propeller. Here’s a handy simulation of exactly how that happens.