At the last club meeting, somebody asked me what those shadow bands really were. Mary McGauley, who had presented the nice eclipse video earlier that evening, remarked they looked like the water ripples one can see on the bottom of a swimming pool. Filming Shadow Bands. A few minutes before second contact and a few minutes after third contact, when only a narrow crescent is visible, the scintillation phenomenon known as shadow bands occurs. According to various reports, the width of the shadow is between a few centimeters and 20 cm, the interval between them several decimeters to one meter, and their velocity several meters per second.
Shadow bands are particularly clear on white surfaces.
As the solar crescent grows narrower, the shadows become longer and greater in contrast and faster. The separation zone was not bright, but rather less dark than the bands themselves. This site also shows 2 images from the video Eric took. Note these bands are moving, which make them very difficult to photograph. Even Eric remarks that, though he used a polarization filter on top of the UV filter, his success was thought to be entirely due to the shadow bands just being much more pronounced during this eclipse.