A bonus post! Last Sunday, Geoff and I headed to the Waterford River waterfall to try out my new ND110 filter. An ND filter works like a dark pair of sunglasses in that it reduces the amount of light that passes though the camera's lens. In order to get enough light for a properly exposed photo, the shutter must be left open for a longer period of time than what would be necessary when no filter is being used. This means that any moving elements (in this case water) will become blurry, while the rest of the photo stays properly exposed.