Seeing so many waterfalls every day I started to play around with my camera to get this cool silk effect. And actually it's pretty easy and you can do it with any camera that allows you to control the shutter speed. Just get out into the wild, find a nice waterfall (preferably with not so bright ambient light), mount it steadily on a stone or trust your calm hand and hit the button. I found 0.2-0.3 seconds shutter to work well. Here are my first 2 tries + awesome morpho butterfly.
Read next
From @mcsvi