Before I started with photography I always loved spending time by a waterfall or river. You really feel their power, especially if it's a big waterfall like the Dettifoss or Skogafoss in Iceland. Then you realise how small you are on this planet. And the rush of the running water allows you to forget about anything around you and this is exactly what I'm trying to catch with my camera.
Mostly I use a neutral density filter (ND Filter) to let the water look like a silver veil for that surreal look. But HOW is your question I guess, so let me explain.
First of all you definitely need a stable tripod, a good digital camera and mostly also a ND Filter which allows you to have a slow shutter speed. This slow shutter speed is relevant for the motion blur effect in the photo on the top.
So now you learned that the shutter speed is responsible for the surreal effect, called motion blur effect. How long this shutter speed has to be depends on the velocity and amount of the running water. Sometimes a 1/4 of a second is already enough to give the water a soft touch. In that case you don't even need a ND Filter, all you have to do is to set the ISO on the minimum (ISO 50 or 100) and stop down the aperture to f/8 or more. You also have to be aware that the overall sharpness of a photo is relative to the aperture. When you stop down to f/22 you will have a long exposure but also a less sharp photo. To explain why this happens would take too much time. All I can say is that the smallest aperture with a APS-C camera shouldn't be over f/13 but this depends also on the lens quality. Some lenses can go higher (f/22) with good sharpness and some can't. I recommend you to go out with your camera and take a few shots of the same object with different aperture (focus manually on one specific point) so you get to know your lens.
When it comes to the point where you can't close your aperture more, then you have to use a ND Filter. Those filters are available with different density and in different qualities from different brands. Normally I use the B+W 106 ND 1.8 or the B+W 110 ND 3.0 to get an exposure time 64 times or 1000 times longer than without ND Filter. If you use a ND Filter, please focus manually, use ISO 100 and take first a picture without ND Filter. As soon as you are happy with the brightness in the photo then you keep the shutter speed and the aperture in your mind. Go to manual mode "M" on your camera, set the aperture (f/x), the shutter speed (X/XXs) and the ISO again on 100. Now check the focus again and stick on the ND Filter and multiply the shutter speed with the number 64 or 1000, depending on the density you use, and press the trigger in self timer mode.
What you get is a photo with motion blur effect and you can still change the strength of the effect when you change the aperture to get a shorter or longer shutter speed. But don't forget that the aperture is responsible for the amount of light which goes on to the sensor. So if you stop down one full stop, you also have to take the photo with double shutter speed. Well what is a full f-stop. On your camera you have 1/2 or 1/3 or other f-stops, so I give you here the full f-stop row:
f/1,0 - f/1,4 - f/2 - f/2,8 - f/4 - f/5,6 - f/8 - f/11 - f/16 - f/22 - f/32
From each number to the next higher one the light quantity is halved. For example:
As you can see now the row of the shutter speed is changing. The same happens if you change the ISO, when you double the ISO from ISO 100 to 200 the shutter speed halves and if you lower the ISO by a full stop, the shutter speed doubles. That's how the ISO-row works:
ISO50 - ISO100 - ISO200 - ISO400 - ISO800 - ISO1600 - ISO3200 - ISO6400 - ISO12800 - ISO25600 etc.
The last thing to know is, that you always should switch off the image stabilizer when you use a tripod and to save the images in RAW for better post-processing capabilities in Lightroom or similar software.
I would be grateful for constructive comments in the Guestbook to improve my workshops, thank you!
Öxarárfoss in ÞingvellirTaken with B+W ND 1.8, f/9 and a shutter speed of 2.5sec. ISO 100 View form DyrhólaeyTaken with B+W ND 3.0, f/7.1 and a shutter speed of 10sec. ISO 100 SeljalandsfossTaken withe B+W ND (unknown), f/6.3 with a shutter speed of 13sec. ISO 100