Lake Ha Hand lies about 20 miles northwest of Yellowstone National Park. On a calm morning when it is lit by golden sunshine it is spectacular. The lake’s outlet offers an interesting foreground to begin your visual journey into the scene. Since the foreground was still in deep shade, five images were shot at different exposures by changing the shutter speed. These images were processed with Photomatix Pro to produce a single image where detail is revealed everywhere. If High Dynamic Range techniques had not been used, most of the shadows would have been nearly black and lacked detail. Canon 1D Mark III, Canon 24–105mm lens at 30mm, ISO 100, f/22, shutter speeds of 1/30, 1/15, 1/8, 1/4, 1/2 second, Sun WB, polarizer, manual exposure and AF-C autofocus on the back-button.
Conquer Extreme Contrast with HDR
The typical sunrise scene has a dark foreground and a bright red sky. The range of light is extremely high in contrast. The contrast is so significant that it is nearly impossible to capture detail throughout the scene. When the brilliant red sky is beautifully exposed, the foreground is too dark and lacks detail. When the foreground is exposed optimally, then the sky is hopelessly overexposed and most detail is lost. This is a common problem. The extreme contrast between a mostly white waterfall and dark-green moss on the rocks bordering it cannot be captured with detail in both.
As you look closely at a subject high in contrast, you can see detail in both the highlights and the deepest shadows, yet no camera is able to capture this light range in a single image. The camera is only able to capture detail over a range of several stops of light, but your eyes are able to easily see detail everywhere. Partly this is true because we can see a wider dynamic range of light than the camera. Also, our eyes quickly adjust for different brightness levels as we scan a scene high in contrast. Although the aperture size varies in the lens, when you shoot the image, you can only use one size at the moment of exposure to cover everything in the image.
Many scenes are plagued with high contrast. The worst cases are those that have the two major causes of contrast at the same time. The first is a scene containing both black and white objects. The contrast is due to the objects that have different reflectance values. The second source of contrast would be a bright sun illuminating one part of the scene while other parts are in deep shade. The worst contrast case occurs when dark objects are in the shade and light objects are lit with much brighter ambient light. In such cases, the contrast range can easily exceed ten stops of light. HDR is an acronym for High Dynamic Range and it is often called High Dynamic Range Imaging (HDRI). It is a shooting method that allows all tones in the scene to be captured, no matter how expansive the dynamic range. No longer must we accept the contrast limitations of our cameras and display devices. HDR offers everyone the opportunity to capture images that look more similar to what their eyes can see because the technique readily handles a much larger dynamic range than our cameras.
Some photographers still object to HDR because it effortlessly produces images with detail in the highlights and the shadows that no single image can capture. They claim it looks unrealistic. Indeed, HDR processing can make images look completely unnatural—even surreal—and it is dubbed the grunge look, but it can also make the image look far more similar to what the photographer saw with their own eyes when viewing the scene. Photographers who believe HDR is always unnatural are accustomed to viewing images that suffer from the limitations of film and single capture digital images. We no longer need to be encumbered by high contrast limitations.
The first of a two-shot exposure bracket varied by two stops of light. The first is the lightest image. Notice plenty of detail and color in shaded Sedge Meadows, while at the same time the sunlit clouds and mountain peak are overexposed. Nikon D4, Nikon 14–24mm f/2.8 lens at 18mm, ISO 200, f/16, 1/5 second, Cloudy WB, polarizer, manual exposure and AF-C autofocus on the back-button.
The darker exposure retains detail in the sky and sunlit mountain, but the shaded foreground and creek are too dark. Nikon D4, Nikon 14–24mm f/2.8 lens at 18mm, ISO 200, f/16, 1/20 second, Cloudy WB, polarizer, manual exposure and AF-C autofocus on the back-button.
The scene after merging the first two images together with Photomatix Pro and final processing with Photoshop CS6. Detail and color are retained in both the sky and the shadowy meadow. Barbara shot two images as quickly as possible so neither the horses nor the clouds moved between the exposures. Since horses tend to move a lot, she shot several two-image exposure brackets and selected the one set in which neither had moved.
A LITTLE HISTORY ON SOLVING HIGH CONTRAST
When black and white film was popular, dodging and burning were widely practiced darkroom techniques that helped to overcome high contrast problems. Ansel Adams is famous for his mastery of burning and dodging and wrote a book—The Negative—explaining his fabulous techniques. Black and white remains quite popular today, but most of it is currently achieved with software and digital cameras.
SPLIT NEUTRAL DENSITY FILTERS
For years graduated neutral gray-colored filters (GNDs) have been used to reduce the contrast in a scene and we used many ourselves in the past. These filters are sold in various strengths. One half is clear and the other half is darkened by various degrees of light. For example, common ones include two and three stops of neutral density. If the scene’s foreground is four stops darker than the sky, putting a hard edge three stop GND filter on the lens and positioning it to make the dark side cover up the bright sky and the clear side coincide with the dark foreground effectively lowers the contrast to only one stop of light. The filter works well if the scene has a fairly straight horizon, which allows the filter’s edge between the light side and the dark side to fit neatly along the horizon line. However, most horizons are not straight. If a tree pokes above the horizon, the portion of the tree is unnaturally dark relative to its base.
Some neutral density filters have a gradual break to help it dissolve into the scene and make it less obvious a filter is being used. While this helps somewhat, the horizontal edge of the filter is usually still apparent. If you have three expensive graduated neutral density filters in one, two, and three stop strengths, what do you do if seven stops of contrast must be overcome? Perhaps one might stack all three of the filters together, but image sharpness suffers because the light must pass through more glass surfaces. Graduated neutral density filters work, but their expense and shortcomings often make them an unattractive way to shoot.
A BETTER WAY TO OVERCOME CONTRAST
High Dynamic Range imaging (HDR) offers a far better way to handle extremely high contrast. HDR can handle any contrast range and it does not matter where in the image the contrast edges occur. You do not need to carry a set of filters to handle different contrast levels and the contrast does not have to align with any edge. Even if you had to capture three large areas of dark and light, you could easily accomplish it with HDR techniques. You can easily and accurately capture three dark rocks in a sea of snow, showing the wide range of tones encompassing the scene. HDR works far better than any filter could. However, the limitation for using HDR is that the subject must remain still long enough to shoot several images without moving the camera.
Many photographers use graduated neutral density filters to control contrast. We once did as well, but have now abandoned them in favor of HDR techniques. Unlike graduated neutral density filters, HDR handles all contrast ranges if you bracket widely enough, and it does not matter where the deep shadows and bright highlights occur in the scene. The contrast in the shadows of Scott Fall near Munising, Michigan, and the sunshine on the aspen leaves do not provide a regular edge to hide the effects of a neutral density filter, but HDR deals with this situation handily. Nikon D4, Nikon 14–24mm f/2.8 lens at 14mm, ISO 100, f/16, shutter speeds of 1/4, 1/2, 1, 1/2.5, and 5 seconds, Sun WB, manual exposure and AF-C on the back-button.
HDR requires the subject to remain motionless between exposures. However, when there is movement in part of the scene that was not expected to be sharp anyway, then HDR works to control contrast. The cloudy sky above Union Falls in Yellowstone’s backcountry, and the dark rocks and bushes at the bottom of the canyon, create too much contrast to be fully captured in a single image. Detail is captured everywhere by shooting two exposures and merging them together with Photomatix Pro. Canon 1Ds Mark II, Canon 24–105mm f/4 lens, ISO 100, f/16, 1/5 and 1/10 second, Cloudy WB, manual exposure and autofocus on the back-button.
HDR requires shooting a series of images of a still scene in which you vary only the shutter speed to capture the brightness range. For best results, the exposure should vary by at least one stop of light, but not more than two stops, to get a better transition between the tones. Of course, you could use increments of 1.3, 1.5, or 1.7 stops of light if you prefer. The idea is to properly expose every brightness in the scene in at least one of the images making up the exposure series. The greater the contrast range, the more images that are needed to cover that range. Although this technique works best with still scenes, it could be used when part of the scene is moving and not expected to be in sharp focus in any case. Waterfalls, rivers, and crashing waves are all commonplace examples.
SHOOTING THE HDR IMAGES
It is best to shoot the exposure series of images using the RAW format. JPEGs have only 8 bits of data. The camera processes and discards a considerable amount of the data when compressed into an 8-bit file. This causes artifacts (flaws in the image) and doesn’t offer enough values to produce fine transitions in the image. If your final goal is a JPEG, it is best to shoot the exposure bracket using RAW, then produce the HDR image, and finally convert it to a JPEG. Nevertheless, if you shoot only JPEGs, HDR still helps considerably to tame contrast.
To make the images in the exposure series align and merge with the fewest problems, be sure to keep several factors identical between images. Do not change the ISO, focus, white balance, polarizer position, or aperture. Vary only the shutter speed. You can use manual metering or aperture-priority. Both metering modes are excellent for keeping the same aperture between exposures to avoid huge depth of field differences.
Mike Nolan, owner of Timber Ridge Lodge where we host our Michigan workshops, is fond of his vintage 1954 truck that still hauls frewood. I remember the year well because I was “made” in 1954, too. I think this truck has weathered the years much better than I have—and Barbara agrees! Every autumn Mike parks the truck under the maple trees to enable our workshop members to photograph it with autumn leaves decorating it. The contrast between the light areas of the truck and the black tires is easily subdued using HDR. Nikon D300, Nikon 28–200mm lens at 56mm, ISO 200, f/22, shutter speeds of 1/2.5, 1/1.3, 1.6, 3, 6, 13, and 25 seconds, Cloudy WB, polarizer, manual exposure, and AF-C autofocus on the back-button. Processed with Photomatix Pro and finished with Photoshop CS6.
Most photographers rely on autobracketing to shoot an HDR series. Consider a typical scene in which there are seven stops of light differences between the brightest highlights and the darkest shadows. If you shoot a five-image bracket where each exposure varies from the other by two stops of light, a ten-stop range of light will be covered. When you run the five images through HDR processing software, the software selects the well-exposed parts out of each image and assembles them into a single image in which everything in the image will be beautifully exposed with ample detail.
Autobracketing is effective with some cameras. However, many cameras only offer a maximum of three images when autobracketing. Usually this is not enough to cover the dynamic range of the scene. Also, it is time consuming to bracket exposures wider than necessary. If only six stops of contrast need to be covered, then shooting five images to cover ten stops is unnecessary. Quality can suffer, too. Many photographers speed up the autobracketing process by using high speed shooting or the burst mode. They rapidly shoot the series of images. However, using burst mode to shoot the images is a terrible idea, especially with the longer shutter speeds so commonly used when doing HDR. The loss of sharpness is a serious problem due to camera-shake that is caused by the action of the mirror and the shutter. If the tripod-mounted camera shoots five shots one after the other and the exposures are around 1/15 second, the first image may be sharp, but the slight camera-shake caused by the mirror moving up and down and the opening and closing of the shutter may vibrate the camera and unnecessarily cause a slight loss of image sharpness in the remaining images. Most photographers pay little attention to this problem and like their results regardless, but why give up some image sharpness needlessly? Hopefully, everyone wants all of the sharpness they can get! Autobracketing will work when you set up the camera to wait for you to trip it with a cable or remote release between images. This allows you to wait a few seconds between shots to allow any motion that is caused by the shutter and mirror mechanisms to quiet down.
Many cameras allow you to shoot only three-image exposure brackets. It is possible nonetheless to cover a wider dynamic range. Set the exposure compensation control to +2, shoot the three-image bracket using two stop increments and now you have a series of exposures that are 0, +2, and +4 stops of light. Next set the exposure compensation control to –2 and shoot another three-frame bracket to produce three additional exposures at –4, –2, and 0 exposure compensation. You must delete one of the two duplicate exposures at the 0 compensation. Five exposures will be left covering a range of –4, –2, 0, +2, and +4 stops—an eight stop contrast range! For many outdoor scenes, this range covers the contrast quite adequately. However, some scenes may well have a higher contrast range.
MANUAL HDR EXPOSURE BRACKETING
We prefer to shoot our HDR image series manually without using autobracketing. This is our procedure. This works perfectly for all cameras and is not dependent on any camera capabilities for autobracketing because you bracket the exposure manually by changing the shutter speed. Also, there is no need to worry if you are covering the dynamic range of the scene because you are assured of doing it by monitoring the histogram data. It is such an obvious, effective, and painless way to shoot the exposure series that it is surprising this method of doing it is not more widely known and utilized. Try this series of steps:
1.Set the ISO, white balance, focus, aperture, and polarizer position (if used). Do not change any of these while shooting the HDR series. Only the shutter speed should vary to accomplish the exposure changes. It is possible to use flash as a portion of the light. Be sure to make certain the flash angle and output doesn’t change from one shot to the next.
2.Shoot on a tripod to get the optimum sharpness and to lock in the composition, which allows the software to align the elements in the image hassle free. Most HDR programs offer some ability to align the images when you shoot handheld, but everything works so much better when using a sturdy tripod. Even when using a tripod, however, movement can still be a problem. Running water, crashing waves, soft ground, and wind can all move the tripod. Wind can make grass and branches blow, so watch out for subject movement as well.
3.Before shooting the first image, put your hand in front of the lens and shoot an image to indicate the beginning of the HDR series. Otherwise, when editing, you may delete the first image before you realize it is an exposure bracket and then have to waste time retrieving it from the bit bucket.
4.Expose first to preserve detail in the brightest highlights. The best way to do this is to determine the starting exposure that produces no flashing highlights (blinkies) on the LCD display when the highlight alert is activated and the rightmost histogram data fall about one stop short of the right wall of the histogram.
5.To get slightly smoother contrast transitions in the image, use one stop brackets and slow the shutter speed down by one stop for each exposure. Be sure to turn the shutter speed control gently to avoid jarring the camera and changing the composition slightly. Using one stop increments will require you to shoot more images, so it takes more time to shoot the series and later process it using software. Remember the guideline for HDR is to shoot the exposure brackets in at least one stop increments, but no more than two stops.
6.Continue to slow the shutter speed down one stop at a time and continue to shoot images until the leftmost histogram data are about two stops from the left wall of the histogram. The highlights will be pitifully overexposed and blinkies will be prevalent, but the goal is to capture excellent detail in the deepest shadows with little noise. Expose to get the leftmost data away from the left wall to reduce noise in the darkest shadows.
7.When the leftmost histogram data move two stops to the right of the histogram’s left wall, the image set is concluded. It assures capturing detail in the darkest and brightest tones and everything in-between. The number of images making up the series depends entirely on the difference in brightness of the blackest shadows and the brightest highlights. At least one image in the series captures every brightness level.
8.Photograph your hand once again to mark the end of the HDR image series.
High Dynamic Range imaging techniques are efficient for handling the high contrast at sunrise and sunset. As the first red rays of sun light up the mountains to the west of Lake Ha Hand, the color refects splendidly in the calm water. A three-shot exposure bracket varied by two stops each adequately handled the contrast range. The exposure for the first shot slightly underexposed the white snow on the mountain. Then the shutter speed was slowed by two stops for the second image. Finally, add two more stops of light to capture detail with less noise in the darkest portions of the scene by slowing the shutter speed down two more stops. We prefer doing this manually, rather than using autobracketing. By carefully processing the image, we think it appears exactly as it did while we were standing there viewing the scene. Canon 5D Mark III, Canon 24–105mm f/4 lens at 38mm, ISO 200, f/16, shutter speeds of 1/8, 1/2, and 2 seconds, Cloudy WB, manual focus and exposure. The three exposures are merged with Photomatix Pro and final processing is done in Photoshop CS6.
PROCESSING THE HDR IMAGES
CAMERA PROCESSING
Some cameras offer in-camera HDR processing. Try HDR if your camera offers it. For example, if you have a Canon 5D Mark III, go to the HDR Mode menu selection to find five choices: Disable HDR, Auto, ± 1 EV, ± 2EV, and ± 3EV. The Auto setting allows the camera to automatically determine the bracketing amount in stops. Otherwise, you make the choice of one, two, or three stops. The Effect can be set to produce Natural, Art Standard, Art Vivid, Art Bold, and Art Embossed. Use these to determine how the image appears. Art Vivid accentuates the color whereas Natural is more subdued. Continuous HDR can be set for 1 Shot Only or Every Shot.
When set for 1 Shot Only, the camera allows a three-image exposure bracket, processes the images, and creates the HDR image. It then reverts to normal shooting. You must reset the camera to be able to shoot another HDR image. Every Shot keeps the HDR mode activated for additional shots. The Auto Image Align offers two choices—Disable or Enable. When shooting handheld, be sure to set Enable. The last decision is Save Source imgs. The default choice is All Images. If you do not wish to keep the source images, then set HDR img Only. The camera discards the source images and keeps only the combined HDR version. Keep in mind you may want to retain these source images to be processed with another HDR software program. Due to technical reasons, the final in-camera processed HDR image is outputted as a JPEG and cannot be saved as a Canon CR2 RAW file.
I have used this feature and it surely helps control high contrast situations, but the results certainly are not of the same quality as HDR images processed with dedicated HDR software. In-camera HDR is a respectable place to start, but for the ultimate quality and flexibility, plan to use a more robust HDR processing program, such as those that follow.
SOFTWARE SOLUTIONS
Once you shoot a series of images that capture detail in all of the tones found within the scene, the images are processed with software. During this process, the brightnesses are tone mapped to shrink the dynamic range of light in the scene. This allows everything in the image to appear with detail. Process the images carefully to avoid introducing artifacts that include noise, ghosting, and haloes. Said another way, tone mapping must be done to enable detail in the bright and dark areas to be preserved and viewable.
There are many outstanding HDR software programs that work well. A short list follows, but you can find others by searching for “HDR software choices” on the Internet.
Canon Digital Photo Professional www.usa.canon.com
EasyHDR www.easyhdr.com
HDR Efex Pro www.google.com/nikcollection
Oloneo HDR www.oloneo.com
Photomatix Pro www.hdrsoft.com
Paintshop Pro X6 Ultimate www.corel.com
SNS-HDR www.hdrlabs.com
Photoshop – Merge to HDR Pro www.adobe.com
SOFTWARE OPTIONS
HDR processing software has been available for several years and continually improves. Photomatix Pro is considered the gold standard, but now there are many programs that are first class. You may already have one and not even know it. Indeed, the latest version of Canon Digital Photo Professional that is packed with new Canon cameras has a useful HDR program to get you started. Endless ways to process your HDR images are available. It is possible to make the images appear real, completely out-of-this-world, and everything in-between. The processing details are beyond the scope of this chapter. Entire books are devoted to HDR and tons of excellent free information is available on the Web. Go to the website for Photomatix Pro (www.hdrsoft.com) and look under Resources for excellent leads to terrific information.
A summary of the way to process images using Photomatix Pro follows. This is a fully-featured program that provides numerous options and tweaks. It is not difficult to get a fine result, but it takes experience to gain control over everything it can do. Here is the basic process from beginning to end.
1.Shoot the Images
Bracket the exposure with a minimum of one stop exposure increments, but not more than two stop increments. Use a tripod to keep the images aligned. However, Photomatix has an alignment feature to help position the images that are shot handheld.
3.Load the Bracketed Images
A straightforward way to load the images would be to select the files using Windows Explorer and drag them into Photomatix Pro. Another way is to use the File menu and click on Load Bracketed Photos. A dialog box will ask you what to do with the files. Select Merge for HDR Processing and click OK.
4.Preprocess and Merge the Photos
Align Source Images offers two choices. If you shot the images handheld, check By Matching Features. If shot on a tripod, check By Correcting Horizontal and Vertical Shifts. If any objects or people move in the images, check Reduce Ghosting Artifacts. Now choose between Automatic or Semi-Manual with the latter choice producing the best results most of the time. If the loaded images are RAW files, check Reduce Noise and On Source Images.
5.Click on Preprocess
The Settings window allows you to adjust the process, method, and settings. There are two processes. Tone Mapping is applied to the merged 32-bit HDR image. It offers far more versatility and many different “looks.” The two tone mapping methods offered include Details Enhancer and Tone Compressor. The second process is Exposure Fusion, which combines the source images directly and tends to produce more realistic-looking images. Try both ways to see which you prefer.
6.Press the Process button and save the results
The six steps are the basics for using Photomatix Pro software. There are many more options available for fine-tuning the image. The basics are pretty straightforward. Even I could do it without any help and I was absolutely computer illiterate (slightly better now) when I first tried it in 2011.
SINGLE IMAGE HDR
High Dynamic Range remains the best way to capture brightness extremes found in many scenes that make them impossible to capture with a single image. It is effective for still scenes, but ghosting and alignment problems must be dealt with when objects move during the exposures. It is possible to take a single RAW image and process it twice to help tame contrast problems. Process the RAW image to retain excellent detail in the highlights. Process it once again to get the best detail in the darkest shadows. Take these two results and process it with HDR software. The result should be better than merely processing one of the images, but don’t expect it to be as good as literally shooting a series of bracketed exposures. Of course, if objects in the image are moving, then it is not possible to shoot multiple exposures while keeping the objects in the same spot, so you do not have a choice and single image HDR processing remains the best solution.
Many photographers object to HDR because they think it makes the image look artificial. Evidently, too many HDR images have been overdone and some have come to believe unrealistic images are the norm. HDR techniques can look real or unreal. It all depends on the processing skills and the intent of the photographer. Barbara deliberately overdid the hot air balloon at the Wooden Shoe tulip field in Woodburn, Oregon, just for fun. It is called the grunge look. We don’t want most of our HDR images to look this way, but it is fun to process a few this way. Nikon D4, Nikon 14–24mm f/2.8 lens, ISO 200, f/16, shutter speeds of 1/20 and 1/80 second, Sun WB, AF-C on the back-button and manual exposure.
The contrast between the red sunrise behind our campsite in the Lee Metcalf Wilderness northwest of West Yellowstone, Montana, and the shaded meadow is too immense to capture in a single image. Running the exposure bracket through Photomatix Pro resulted in this image. Since the software selects mid-tones out of each of the images in the bracket set, usually the final result produced by HDR software is too low in contrast. Nikon D4, Nikon 14–24mm f/2.8 lens, ISO 200, f/13, shutter speeds of 1/10, 1/15, 1/20, 1/40, and 1/80 second, 10,000K WB, AF-C on the back-button and manual exposure.
The final image after Barbara worked her magic in Photoshop CS6 and added a bit more contrast by brightening some of the lighter areas in the scene.
STILL MORE PROCESSING
We find the results of running a stack of images through HDR software agreeably reduces the contrast range to more accurately reveal what our eyes can see. However, the final result is quite often a little too low in contrast. This occurs because the software selects the well-exposed portions of the images. Bright whites and dark blacks are often lacking in the final HDR result. Oddly enough, a little contrast is useful in the final image. Barbara runs the final result from the HDR processing through Photoshop to reset the black and white points to add a little more contrast, which results in having more detail over a wide dynamic range.
HDR offers the opportunity to subdue high contrast. HDR is one of the top six most powerful new photo techniques to come and be a true game-changer during my forty-year career as a full-time outdoor photographer. Be sure to take advantage of it. You may be curious about the other five game-changers. We will cover the game-changers later, but to tweak your interest, they include panoramas, focus stacking, high ISOs for the night sky, in-camera multiple exposures, and sophisticated uses of wireless flash for landscape and close-up photography.
While enjoying a ranger-led tour of these protected ruins in Mesa Verde National Park, Barbara used her widest focal length lens inside this tiny underground room. Due to the wide dynamic range, she shot eight exposures in one-stop increments and combined them into one image using Photomatix Pro. Nikon D4S, Nikon 14–24mm f/2.8 lens at 14mm, ISO 100, f/18, 1/4, 1/2, 1, 2, 4, 8, 15, 30 seconds, Cloudy WB, manual exposure and AF-C autofocus on the back-button.