Use a Tripod
Balance your camera securely on a tripod, rock, flat wall, or similar steady surface. To produce the silky effect in many running water photographs, you’ll be using a long exposure, so the camera must stay still and steady. Holding a camera at these longer exposures will create a blurry image.
Use a Slow Shutter Speed
Meter your shutter speed using a light meter, if possible. If you don’t have one, give your camera an exposure of at least 1/2 second and adjust from there. A slow shutter speed will blur the water and give it that heavenly feel.
Use a Small Aperture
Stop down to an aperture of at least f/22. This will allow for a large depth of field to keep everything in the image in focus. It will also require the use of a longer shutter speed. These two factors work together to create the best waterfall pictures.
Use a Neutral-Density (ND) Filter
ND filters reduce exposure and are very useful in achieving those slow shutter speeds while allowing for a large depth of field.
Use a Low ISO
The lower the ISO, the less noise the image will have. Always use the lowest ISO possible to create the highest-quality images. The low ISO will also slow down the shutter speed. An ISO of 100 is best for waterfall shots.
Use Low Light
By slowing down the shutter speed, you’ll increase the light that gets into your camera, risking overexposure. Less natural light will help prevent this issue. Shoot at sunrise or sunset, when the color temperature of light is more forgiving. If this is not possible, chose an overcast day rather than a bright, sunny one.
Take Your Time
By now, you might have noticed that strategies for photographing running water center on slowing down the shutter speed. This type of photography is all about patience, so take your time. Calculate every step and pay close attention to composition and perspective. Practice often, and before you know it, you’ll have that dreamy waterfall image you’ve envisioned.