I'm not sure either but I think that the longer exposure was not neccessary. I was in aperture mode and the camera adjusted exposure time to 30sec automatically. I think (but would like to know your inputs on this) that if I used full manual I could have decreased the shutter speed?
![Gold Star Critiquer/Gold Star Workshop Editor/Gold Note Writer [C: 1976 W: 259 N: 4103]](http://i1.treknature.com/misc/g-g-g.gif){kind=small}