Waterfalls are one of my favorite subjects to photograph. I typically like to use a slow shutter speed to capture the motion of the water. This can be problematic during bright lighting conditions, as the situation will typically call for a fast shutter speed. To ameliorate this, I use a polarizing filter, along with a number of neutral density filters, to reduce the amount of light passing through the lens, allowing the use of a slower shutter speed. A polarizing filter also helps to reduce glare and reflections from the water surface, wet leaves, rocks, etc. A sturdy tripod and remote shutter release are especially important to ensure a sharp photograph, free of any camera shake.