Blurred water: Fiction and facts

Some people don’t like the silky water effect. While I agree that at times it verges on cliché, the truth is that fast water illuminated by anything less than full sunlight usually offers little choice. In those conditions the question isn’t whether to blur the water, it’s how much?

The argument against blurring moving water that always amuses me is the one that says blurred water “isn’t natural.” The reasoning here is that blurred-water images should be disqualified because we never see blurred water in nature. To these “purists” I ask, how many times have you seen the alternative: individual water droplets suspended in midair for permanent scrutiny? This just underscores a photographic truth I’ve been hammering on for years: The camera and eye record the world entirely differently. Discarding images simply because they aren’t “natural” would not only eliminate all black and white images, it would also eliminate every image that’s not, uh, three-dimensional. Hmmm. Now let’s count how many images that leaves us with….

On the other hand, embracing and leveraging your camera’s unique vision is empowering. It opens the doors to creative possibilities of which blurred water is just a scratch on the surface. While there’s no magic formula, blurred water isn’t hard once you learn to see the world as your camera does.

The prime determining factor in blurred water is the distance any individual water drop moves across your frame while the shutter is open: the more of the frame it spans, the greater the blur. The amount of blur you capture starts with the speed of the water, over which you have no control. But take heart, because there are several variables you can control:

  • Focal length: The longer your focal length (more telephoto), the shorter the distance from one side the frame to the other (a wide angle vista can encompass many miles; a telephoto from the same vantage point can reduce the image’s width to a few hundred yards or less). Since the water moves at a fixed speed, an imaginary water droplet will span a greater percentage of the frame in a telephoto exposure.
  • Subject distance: Moving closer achieves the same thing a telephoto lens does because the closer you are to the moving water, the shorter the distance our water droplet has to travel to span the frame.
  • Shutter speed: The longer the shutter is open, the farther our droplet can travel during our exposure. You can keep the shutter open by reducing your ISO, shrinking your aperture, or cutting the amount of light with a polarizer or neutral density filter.

Because long shutter speeds increase the blur, blurring water is easier when you photograph in reduced light, either overcast or shade. In full sunlight it’s pretty much impossible to blur water without a neutral density filter to cut the light reaching the frame. And you’ll find that the more white the water, the more pronounced the blur. In other words, for any given combination of conditions and settings, while the amount of blur is the same for green water as it is for white water, the blur will be much more noticeable in the white water.

The above image was captured in the late afternoon shade along Mill Creek in Lundy Canyon, just west of Mono Lake. It’s a 1/4 second exposure at ISO 100. I could have gotten more blur if I’d have gone with a smaller aperture (to further reduce the light and allow a longer shutter speed), but I chose f5.6 because I wanted to soften the background make the paintbrush  stand out more.

6 Comments on “Blurred water: Fiction and facts

  1. Thanks Gary. I noticed some stuff like this in Yosemite last year but have been having a lot of trouble sorting out my thoughts on it. This article sums it up really nicely.

    As to the picture, it looks like the flower in the front is a bit blurred. Is this because it was moving or because the depth of field was so small?

    • Thanks, Brad. I focused on the highest flower, which is perfectly sharp. The softness you see in the front flower is caused by the narrow DOF, and maybe some slight wind blur that’s isolated to the lower and closer flowers. The wind had to have been very slight, as flower I focused on was perfectly still.

  2. Hey Gary

    I love this statement: ” how many times have you seen the alternative: individual water droplets suspended in midair for permanent scrutiny”.

    I say this exact sort of thing all the time. LOL. Hope you are doing well.

    • Hey, Leon. Yeah, you gotta take what the conditions give you. In full sunlight you can freeze even a waterfall in complete free fall, but there’s no way you could blur it without significant neutral density help. But really, freezing a sunlit waterfall with a fast shutter is no more natural than blurring a shaded one with a slow shutter. Guess I’m preaching to the choir, though. 🙂

  3. Get way to look at it! I think of it as Art… but really most of life is seen with motion… some faster and some slower!

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