Earlier in the month, I took a trip out to Minneapolis, Minnesota for a friend’s wedding. We made a long weekend of it and worked in some sightseeing. I knew Minnehaha Falls was on my list to see! It was beautiful and very popular! Finding angles to get shots without people was tricky. Another thing I knew I wanted to try was the silky water effect you so often see in water fall shots. Look at the shot above. See how the water looks smooth and continuous? Now look at the shot below–much rougher and more natural.
Smooth, silky water is very popular! So, how do you get it? You’ll need a tripod and a really slow shutter speed. If you are shooting in daylight, you’ll probably need a neutral density filter as well to drop your shutter speed down enough. The top shot I shot at ISO 100, f/22 and a speed of 1.6s. A lower ISO number slows the shutter speed. The higher f-stop number slows the shutter speed. However, without a neutral density filter on my lens, I probably would have had a shutter speed about 1/30 given the brightness of the day. Which would not have made silk.
A neutral density filter essentially is a dark piece of glass you screw onto the end of your lens to make a bright day darker. They come in various degrees of darkness and you can buy them individually or in sets. Amazon sells a bunch of types, as does any camera store. They are handy to cut some of the brightness if shooting midday and to slow the shutter speed when you want to make water silky. They also sell graduated neutral density filters if you want only to cut the brightness on half the shot (such as the sky).
So, in sum, to make silky water:
ISO–set as low as you can (100 or 200)
F/stop–set as big a number as you can (f/22, etc)
Use a tripod–otherwise it will be blurry at such low speeds
Not a low enough speed to make it silky? –use a neutral density filter