I recently had a question from a photographer about achieving the classic blurred water effect that many landscape photographers use during full daylight. The blurry water effect comes from using a long shutter speed (.5 sec to 10 sec depending on speed of water) to allow the motion of the water to appear smooth.  In low light situations it can be easy, and sometimes unavoidable, to get a long enough shutter speed without any assistance. When more exposure time is needed also make sure you are using a tight aperture (f/22+) to let in less light and a low ISO (50-100) to decrease your camera’s sensitivity to light. In slightly brighter conditions a polarizing filter, which holds back about 1 stop of light, can help give a long enough shutter speed to get blurry water. In brighter daylight conditions you might also need to use a neutral density (ND) filter, or combinations of ND filters, to block some light (3 stop up to 10 stops depending on how bright it is) and give you a slower shutter speed. Singh-Ray and other filter makers also have variable ND filters that allow you to “dial in” the amount of filtration you need.