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|Longs Peak from Twin Sisters, Rocky Mountain National Park, Colorado.
HDR Efex Pro Deghosted Noise Reduction—Processed with Nik Software HDR Efex Pro’s Global-High ghost-reduction utility. Noise reduced in Adobe Camera Raw before HDR processing.
Interest in high-dynamic-range (HDR) imaging has exploded over the last few years. More than half a dozen HDR software packages are now available, and for good reason, as HDR imaging promises to solve one of the great challenges of photography: taking the broad range of tones we see in the real world and compressing them into the much narrower range of tones we can reproduce on a monitor or on paper.
Until recently, I was an HDR skeptic, however. All too often, HDR software produced unnatural results. Shadow contrast sometimes looked strangely flat. Colors shifted in odd ways, and dark objects set against bright backgrounds often developed pronounced halos—weird bright bands along the object’s edge.
Granted, HDR software must solve a tough problem: replicating the intricacies of human vision. Our visual system analyzes contrast locally rather than globally. In other words, we don’t look at the darkest part of the overall scene and call it black, then look at the brightest part and call it white. Instead, we analyze contrast within regions, most obviously shadows and highlights, but also more subtly. The challenge for HDR software is to maintain good local contrast within regions, while still creating believable transitions between regions. Simply taking the overall range of tones and compressing it in some linear fashion won’t cut it.
HDR Photomatix EF—Processed with HDRsoft Photomatix Pro 4.0 using Exposure Fusion.
The latest generation of HDR software goes a long way toward solving these problems. In my testing, three programs stood out. HDRsoft Photomatix Pro is best used as a stand-alone program or as an export plug-in for Lightroom; the plug-in versions lack some features. Nik Software HDR Efex Pro can be used as a plug-in for Lightroom, Aperture and Photoshop. Unified Color Technologies HDR Expose is a stand-alone program that also can be used as a plug-in for Aperture and Lightroom. Additionally, HDR Expose has a twin, a Photoshop plug-in called 32 Float.
The most difficult subjects for any HDR package are those that include the sun. Often, HDR software creates unnatural concentric bands around the sun, with sharp transitions between bands rather than a smooth gradient. For my first test case, I chose an image of the sun setting over Pigeon Peak, shot from the summit of Mount Eolus. For my second test case, I picked a high-contrast image of a stormy sunrise over Longs Peak. Using a Sekonic L-608 spot meter, I measured a six-stop range between the dark, shadowed midground evergreens and the glowing clouds. For each test scene, I made three exposures, with exposure compensation values of -2, 0 and +2.
HDR Photomatix TC—Processed with HDRsoft Photomatix Pro 4.0 using Tone Compressor.
To evaluate the results fairly, I needed a standard for comparison. The most useful, I decided, was to take the best single exposure from the bracketed set of exposures and create the best image possible using Adobe Camera Raw. My goal in using each HDR package was to create an image that had better highlight and shadow detail than I could extract from a single exposure, while still looking natural. All HDR software easily can create the wild, over-the-top, “HDR” look; the challenge is to create an image that resembles what we saw. I did no further processing in Photoshop on either the single RAW or the image output from the HDR package, since that would make valid comparisons impossible. All of the HDR packages were able to produce better detail in the highlights and shadows than I could achieve with a single raw file. Beyond that, the programs differed in many respects.
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Unified Color Technologies HDR Expose
Let’s start with HDR Expose and its companion 32 Float, which share the same interface and processing engine. One of the major problems for HDR software is maintaining good local contrast within the shadows. Often, the shadows look like you’re viewing them through a thick blanket of smog. Here, HDR Expose excels with a feature called Veiling Glare that beautifully restores believable contrast to the shadows. Using Veiling Glare is simple: Click on a near-black area with an eyedropper and adjust a slider to taste.
Another standout feature of HDR Expose that’s unique among the packages I tried is Color Tuning, which allows you to tweak individual colors separately from the overall color balance. You start by clicking on the errant color with an eyedropper. HDR Expose then displays a color-picker panel showing the original color as well as closely related colors. Drag a marker to the new color, and HDR Expose updates the old color to the new throughout the image without creating harsh transitions between colors.
Although HDR Expose has several strengths, it’s not perfect. The workflow feels cumbersome and the previews update more slowly than any other program I tested. HDR Expose’s workflow uses a series of operations (Brightness/Contrast, Shadow/Highlight, Veiling Glare, etc.). Each operation appears sequentially in a panel that resembles Photoshop’s History panel. If you want to revisit an earlier step, the software disables subsequent operations temporarily, which makes it hard to judge what changes you should make to the earlier operation. You have to re-enable the subsequent steps to see the full effect of all your changes—a process that can take a minute or more even on my 64-bit, quad-core Windows 7 system with 8 gigabytes of RAM. You can repeat an operation (for example, using Veiling Glare, then Shadow-Highlight, then Veiling Glare again) rather than revisiting an earlier one, but then you’re stacking the same adjustments on top of each other—an imperfect solution. Although HDR Expose produced some harsh transitions around the sun in my first test image, I got excellent image quality in my shot of Longs Peak.
Nik Software HDR Efex Pro
Nik Software HDR Efex Pro is a new entry in the HDR marketplace. In my opinion, it’s a winner. HDR Efex Pro has the fastest, most fluid interface of the three programs that I tested. It’s also easy to understand—which is a good thing because the current user guide is light on details. For example, the first slider in the Nik interface bears the straightforward name Tone Compression. Values greater than zero compress the tones (reduce overall contrast); negative values expand the tones. (By comparison, one of the sliders in Photomatix Pro’s Tone Compressor option is labeled Contrast Adaptation, which their manual says “adjusts the influence of the average brightness in relation to the intensity of the processed pixel.”)
HDR Efex Pro’s second great virtue is the ability to make local adjustments while still in 32-bit mode through the same kind of Control Points employed in other Nik programs. Using Control Points, you can adjust exposure, contrast, saturation, microcontrast and several other parameters within specific regions of the image. HDR Efex Pro’s power to adjust the image precisely, easily and flexibly is unmatched among the HDR packages I’ve tried. It handled the sun in the frame in my Pigeon Peak image more gracefully than any other HDR utility while preserving crisp contrast in the backlit mountain slopes.
Is it perfect? Not completely. For one thing, it lacks a batch feature, which is particularly useful if you’re working on a panorama and need to merge several sets of images with exactly the same settings prior to stitching them together into the final panorama. I also found that HDR Efex Pro has a tendency to accentuate any noise present in the original image, and there’s no noise-reduction feature built in. For example, my Canon EOS-1DS Mark III produces very slight noise at ISO 400. It’s generally only visible in images viewed at 100%. After processing through HDR Efex Pro, the noise is visible even in screen-size images. Be prepared to do noise reduction on either the source images or the final output if your originals have even minor noise. And note that you must be running a 64-bit version of Photoshop (CS4 or CS5 on a PC, CS5 only on a Mac) to use HDR Efex Pro as a Photoshop plug-in. For Lightroom and Aperture, you can use either a 32-bit or 64-bit version.
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HDRsoft Photomatix Pro
Photomatix Pro was the first widely popular HDR program. Now in version 4.0, the great strength of Photomatix Pro is that it contains three very different methods in one package and makes it easy to compare one to the other. (HDR Efex Pro also contains numerous preset HDR methods, but in my testing, only Natural produces the sort of natural-looking results that I find acceptable.) Think of Photomatix’s three methods as increasingly heavy hammers.
Exposure Fusion is the light-duty tool; it’s not actually a true HDR utility. It comes in several configurations, of which Adjust gives the user the most control. Exposure Fusion-Adjust produces very natural results quickly and intuitively when used on scenes with moderately high contrast—perhaps a four- or five-stop difference between important highlights and shadows.
Unified Color Technologies
Tone Compressor is the next bigger hammer. It can retain good detail in the highlights and shadows of higher-contrast scenes, but it has a tendency to shift and oversaturate colors, requiring more work to retain a natural appearance.
Details Enhancer is the sledgehammer method, able to handle the highest-contrast scenes, but it has a bewildering array of sliders that interact with each other in complex ways. It takes considerable time and experience to master the various controls so you can achieve the look you want without endless trial-and-error. Details Enhancer came in second in its ability to handle the sun in the frame in my Pigeon Peak test shots, but sometimes came in first when used on other scenes containing the sun.
So which HDR program is best? For overall ease of use, ability to fine-tune an image to perfection and a believable final product, I would have to pick HDR Efex Pro as long as the source images were shot at ISO 100. Photomatix Pro has effective noise reduction built-in, making it a good choice for high-ISO images, so it has earned a place on my hard drive as well. All three of these packages have more features, quirks and caveats than I have space to describe. In truth, I don’t think you can go wrong. Each of these programs will expand your horizons and let you photograph high-contrast scenes in ways once considered impossible. Give HDR a try. Download a trial version and see for yourself.
You can see more of Glenn Randall’s work, read his new landscape photography blog, sign up for his newsletter and learn about upcoming workshops at www.glennrandall.com.