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Tuesday, December 1, 2009

Tame Your Dynamic Range

HDR Au Naturel • Hybrid Lenses • Pros And Point-And-Shoots

Labels: How-ToColumnTech Tips

HDR doesn’t have to be obvious. This HDR image was taken in Yellowstone National Park on the Yellowstone River using a Canon EOS-1Ds Mark II with a 17-40mm lens set to 17mm. Three images taken two stops apart were used to make up the HDR. The three were processed in Photomatix software.

HDR au naturel

Q When photographing a deep canyon, with dark shadows at the base and bright sky above, is there a way to capture the entire range of light-to-dark tones? I’ve tried HDRs, but it’s a lot of postprocessing time, and I don’t like my results. Is there a neutral-density filter that will render that “V” of light in the background in a natural way?
K. Collard
Prince George, B.C., Canada

A A neutral-density filter is used to darken an image to allow increased exposure time. Graduated neutral-density filters are half clear and half dark, with a narrow, graduated transition between the two areas. The dark portion, positioned against a bright sky, for example, “holds back” the sky and allows sufficient exposure for the darker landscape below the horizon. The problem with graduated neutral-density filters is that the dark area can be positioned in limited ways: high, low or at an angle in the frame. There isn’t a filter specific enough or versatile enough to cover the shape of every blown-out area of every photographer’s image. In film days, we just lived with it. Now we have HDR (high dynamic range) to solve the problem.

Anytime we get a new digital tool, you can count on some photographers to take it to the max and beyond. (Think saturation!) The HDR process can be used to resolve high-contrast subjects and render them entirely natural—that is, as you saw them. Or you can take it many steps farther and create something slightly enhanced or entirely new that no one has ever seen before. The choice is yours, and that’s what I love about digital.

HDR isn’t really difficult if you plan ahead and let the software do the work. Whenever you face a high-contrast exposure problem, take at least three images in increments of either one or two stops apart. In the case of your canyon, you’d be working from a tripod. But you can accomplish this process handheld by setting your camera to multiple-exposure and auto-exposure bracketing, and firing the three images in quick succession.

I’ve used three different HDR software programs. The most difficult, and perhaps the one you already have, is a component of Adobe Photoshop CS2-CS4 and the least controllable. I typically use HDRsoft’s Photomatix ($99) because it gives me a full range of options, from very natural to highly creative (even bizarre). Photomatix is easy to use, but the multitude of output options can become overwhelming. For your purposes, you might look at the inexpensive and simple Pangea Bracketeer ($29.95). The results are quite natural, with only a few options for enhancement, including saturation and contrast.

The bottom line is that you must recognize the problem in the field and capture accordingly. If you want to keep up with the competition, blown-out highlights just won’t pass muster anymore.


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