Why does the harp string appear to vibrate differently in the video?

[jebii]

hello, I'm a first year science undergrad, currently learning about mechanics and waves and so on
there's this vine that's been going around, which shows someone playing a harp - here is the video in question; I personally find it quite beautiful and fascinating. Apparently the phenomena is caused by the camera shutter speed being in synch with the vibration of the string. Is this an example of resonant frequency, or is it something else entirely? Thanks.

 

[phinds]

It's a stroboscopic effect.

 

[Drakkith]

As Phinds said, it's a stroboscopic effect: http://en.wikipedia.org/wiki/Stroboscopic_effect