The process employed to get that silky effect is called motion rendition. If you set your camera with a fast shutter speed, say 1/125 to 1/4,000 of a second, you will usually stop motion. By contrast, if you set it with a slow shutter speed like 1/4 of a second or maybe 1/8 or 1/15 of a second, anything moving very fast will appear blurred in the resulting image. If you photograph moving water at speeds from two to eight seconds you will get very blurred or silky looking water.
Since no one can handhold a camera steady at shutter speeds that slow, you will need to use a tripod. Because you’ll be using a slow shutter speed, you’ll want to compensate by selecting a small aperture like f/22 or f/16 to get the maximum amount of depth of field (sharpness from the front to the back of your image).
Water and rocks often reflect light as glare and adding a polarizing filter will help reduce reflections and deepen the colors. The polarizer will also reduce your exposure by one and a half to two stops which will allow for even slower shutter speeds.
Here’s how I do it, step by step.
- First, I find a scene I like and select the composition I want while hand holding my camera.
- Once I have the composition worked out, I set up my tripod and attach my camera.
- I set the camera on A for Aperture Priority Automatic and the ISO to the lowest possible speed—usually ISO 200 or Low 1.0.
- Then, I thread the polarizer onto the front of my lens. I also attach an electronic cable release so I can fire the camera without shaking the entire rig. I also use the Matrix Metering setting.
- I turn the polarizer until I get a pleasing combination of little or no reflection and the richest colors.
- I set the aperture to a small opening like f/22 or f/16—the camera will automatically set a shutter speed. These settings can be seen in the read out in your viewfinder. The best shutter speeds seem to be between two and eight seconds, but feel free to use aperture openings that will give you other speeds—hey, this is a good time to learn just what happens!
- I carefully squeeze the cable release and review my shot in the LCD panel on the back of my camera.
P.S. I did break the rules of the tripod with these photos, when riding a motorbike, over the North Carolina Mountains, a tripod can cause your not attention when riding (in my case I was riding a Triumph Speed Triple sport bike), so I handled this shots, I was pretty amazed with the results, so critics are more than welcome 🙂
Notes: Pictures taken with Nikon D700 using Sigma 24-70mm f/2.8 DG EX on Lexar UDMA Professional Digital Film