So I bought a 10-stop ND filter for Scott Stulberg’s workshop… but never got a chance to use it. So when we were in Lee’s Ferry and did the waterfall hike, I had to try it out. The 10 stop ND filter is pitch black. You can’t see anything through it when you use it. It’s main purpose is to give waterfalls that silky ‘cotton candy’ motion blur in bright daylight. You focus and compose your photo first, then put the blind filter on the camera (on the tripod), and do a long exposure. Fascinating tool!