Neutral density filters

For long exposures during daylight, you need to reduce the amount of light reaching the image sensor. However, stopping down the aperture to narrower settings f/22 or greater and lowering your ISO simply won’t darken the scene enough for super-long exposures. This is where a neutral density filter comes in. This semi-opaque filter darkens the overall frame by a specific number of stops, thereby enabling you to lengthen the shutter speed.