Waterfalls are among the most popular photographic subjects in the natural world, and why not? They’re attractive and you can find them all over the place. But there are a number of considerations to take into account when photographing cataracts and that’s the subject of this two-part post. In this installment I’ll deal with technical considerations; next time, we’ll consider the aesthetic side of the endeavor.
Establishing Exposure (and the Limitations of Doing So)
We’ve discussed the exposure triad on this blog in the past. (If you’re unfamiliar with the concept, have a look here.) This comes very much into play when photographing waterfalls.
The key to obtaining a good exposure using a digital camera with just about any scene is avoiding blowing the highlights. This is certainly true of waterfalls because the waterfalls themselves—the whitewater, specifically—usually represent the brightest tonal value in the frame. Back in the film era, the general rule of thumb was to spot meter off the brightest white and open up two stops. You’d correctly expose the highlights and all the other tones would naturally fall into place. This is still pretty good advice as a starting point in the digital era. Be sure to check your histogram (and, if you have the capability, check each color channel’s individual histogram to make sure you haven’t blown any of them—blue is the most likely to be overexposed) for confirmation.
One problem with waterfall exposure is that the parts of the scene excluding the whitewater are often naturally underexposed. The dynamic range of such scenes—this is particularly true when waterfalls are set in deep canyons or gorges—is often extremely wide and the avoidance of overexposing the highlights, as discussed above, will often lead to deeply underexposed mid-tones and shadows. This is unavoidable in a single frame, but today’s digital cameras, with unprecedented amounts of dynamic range render this less of a problem than was the case with exposure latitude-challenged transparency films. Less of a problem doesn’t mean no problem, however, and you’ll very likely find yourself wanting to pull up the shadows to render more detail. There are a number of ways of going about this including (but not limited to) a technique that I outlined on my blog a few years ago that I’ve found to be very effective. Whichever approach you choose, simply be aware that you’re almost certain to want to apply some adjustments to deal with this embedded limitation.
Shutter Speed Considerations (Including Filters)
Among the most important decisions you’ll want to make when shooting waterfalls is how to render the look of the water itself. We’ll talk about the aesthetic considerations at some length in the next installment, but for now consider that your choices range from freezing the water (which requires a relatively fast shutter speed) and the so-called “silky look,” which demands a comparatively slow shutter speed. How slow? Well, it depends on the nature of the waterfall itself (speed and volume of the water, the nature of the drop, etc.) but you can expect to need to shoot no faster than 1/15 second and possibly significantly slower than that.
If you go with the silky look—and most people do—there are some significant implications. The first is that handholding is basically out of the question. To render the non-water parts of the frame sharp but the water itself blurred, you’re going to need to utilize a tripod. (Of course, you should be doing this anyway when practicing landscape photography, but I digress. :))
Obtaining the shutter speed you want may require some special equipment. Depending on lighting conditions, simply stopping down the lens as far as it will go isn’t a good idea (it has negative implications for image sharpness, in the form of diffraction) and may not get you where you want to be with regard to the shutter speed anyway. The same goes for dropping the ISO as low as it can be set. A polarizing filter will help slow down the shutter speed—as much as two stops—and has other benefits as well. A polarizer will usually reduce glare and reflections on wet rocks, for example; the vast, vast majority of my waterfall images have been made with the assistance of a polarizer, and it’s a must have accessory when shooting around water generally. I covered the subject of polarizing filters at some length in an entry on this blog a couple of years ago.
You may also want to invest in one or more neutral density filters to help obtain slow shutter speeds. If you’re unfamiliar with neutral density filters I discussed them in this post.
One potential problem is when the slow shutter speed you may want to use makes it difficult to keep other elements of the scene—wind-blown foliage or flowers, for instance—sharp. If you do very little waterfall shooting, you may be surprised just how frequently this matter crops up. The conundrum can occasionally be solved by shooting multiple images and hand blending them in post processing, but sometimes that’s simply not practical. In that instance…well, there’s not much that you can do about it except wait for a lull in the breeze.
The aperture to use when waterfall shooting may not be as simple as selecting the f-stop that best allows you to obtain your desired shutter speed to render the exposure you need. That’s because aperture also has depth of field implications and depending on your composition, you may need to prioritize depth of field. There are times, when photographing certain scenes, that both shutter speed and aperture draw more or less equal priority and waterfall/creekside shooting is a good example of such an occasion. In this entry on my own blog I discuss in-the-field shooting considerations covering a variety of situations, including the shutter speed/aperture matter mentioned here.
In the second post in this series, we’ll discuss some of the artistic considerations that surround waterfall photography.
Thursday Tips is written by Kerry Mark Leibowitz, a guest blogger on 1001 Scribbles, and appears every other Thursday. To read more of his thoughts on photography, please visit his blog: Lightscapes Nature Photography.