Situated in the Dupont National Forest, two and a half hours north west of Charlotte, NC, Hooker Falls allowed me to take photos of some beautiful water falls. For those of you happy to look at pretty pictures...these are for you! For those of you that want to read how I achieved the cloud-like nature of the water, read on below the photos.
The overall concept to create the 'cloud' effect is to produce a long enough exposure to really blur the the water motion as it cascades over the fall. The challenge comes in achieving that long exposure time. In 'normal' daylight, even at your longest exposure time you're probably not going to achieve the desired effect, because to get this effect we're talking about exposures of several seconds, at least. In a few of the photos I took I was using exposures of 30 seconds in bright sunshine! Needless to say, we need some specialized equipment to achieve this.
Of course, I always recommend using a tripod, but you're also going to need a Neutral Density filter. I used a Variable ND filter from Polaroid. The ND filter reduces the amount of light reaching the sensor without altering the color balance, and come in various 'stops' of light reduction. If you're buying a filter for the first time, you'll need to buy the right size for the lens you're going to use, and this is printed on the lens itself.
Keep in mind, that the water is not the only thing in the scene that's moving. At these long exposure times, the wind moving the tree branches, grass moving, etc, are all going to blurred to a degree. Only things that are solid and not in motion will be crisply in focus, that's why you see the 'ghost' effect of the tree branches. At 30 seconds exposure time, someone could walk briefly in front of the camera and not be recorded to the image!
Here's what I did. I set my camera to it's lowest ISO at 100, then estimated an exposure of 30 secs at f8. It wasn't far off as determined by the histogram! From there I calculated half stop exposure adjustments and 'bracketed'. What I found was that a slight under exposure produced a more pleasing end result.
Of course, every time I moved my position, I had to recalculate my exposure and bracket each one. I found that for this particular set of shots, a 6 second exposure at f29 produced the effect I was looking for with just the amount of blur to remain pleasing. Setting my aperture to f29 also meant a maximum depth of field and a more manageable shutter speed. I used the histogram to help me determine the exposure adjustments I needed.
I've listed the exposure settings under the photos, but for a more detailed article on the challenges I faced in capturing these images, click here.