About HDR – High Dynamic Range Imaging
High Dynamic Range Imaging (HDRI or just HDR) is an extremely popular and useful digital photography tool that has become all the rage in recent years, and for very good reasons. Originally developed for use in the visual effects industry to light computer generated objects, HDR was once a well-kept secret in Hollywood’s CGI artist community. Now a much more mature technology, HDR has found its rightful place in digital photography, resolving the age-old film (analog) photography dilemma of whether to expose (meter) for the highlights or shadows. HDR allows photographers to capture the full range of luminosity in a scene, despite great differences in tonality. From bright highlights to the deepest shadow details, HDR captures it all. With so much tonal information available in an image, the bar has been raised to new heights, yielding stunning images and prints with a near three-dimensional look and feel.
HDR has been in my arsenal of tools since 2007, long before it became du jour in the world of digital photography. It has been said that HDR is akin to a digital negative on steroids, and with that I concur. HDR has opened up an entirely new world to me, as I am now able to capture the full tonal range in a scene. My photographs are no longer limited by outdated technology, and I can now convey those scenes as I experienced them both visually and emotionally – without compromise. In HDR imaging, multiple but separate exposures of the same scene are taken in quick succession at a fixed aperture with the camera mounted on a sturdy tripod. Only the shutter speed is varied, generating shots ranging from underexposed to normal to overexposed. Those individual bracketed shots (Camera RAW file format, not jpeg) are then combined into a single, large, high bit-depth digital file using special software that correctly maps the tonal values, showing great detail throughout the entire image, from the shadows to the midtones to the highlights.
If you have ever tried to photograph a scene with great contrast (dynamic range), you may appreciate the frustration of losing important details in areas ranging from very dark to very bright. For example, shooting a beach scene at sunset creates a dilemma in terms of whether the exposure should be set for the bright colors in the sky, or the darker details at or near the water’s edge. The camera will attempt to average light across the entire scene, but in doing so, will compromise details in one area or another. This means if you want to maintain the rich, colorful details in a bright sky at sunset, the darker foreground details will be sacrificed and lost. In contrast, if you were to expose for the darker foreground (water, people, rocks, tide pools, etc.), the fiery sunset would end up overexposed and washed out as a result. The camera’s sensor is simply incapable of capturing the large dynamic range present in these types of scenes. What is a photographer to do?
Welcome to High Dynamic Range Imaging, a technique used to avoid such terrible compromises. Since the human eye has a much, much greater dynamic range than that of a camera’s sensor (or film, for that matter), what you are able to visualize when present at a scene is not necessarily the result you will achieve post-capture. Dynamic range is simply the variation in luminance (intensity of light) from the darkest to the brightest areas of a scene. In essence, HDR is a digital method to capture and post-process multiple images to create one with a greatly enhanced tonal range. Each bracketed shot contributes important tonal information: underexposure captures highlight details; overexposure captures shadow details; and normal exposure (as metered) captures midtone details.
Of course it is unnecessary to employ HDR when a scene has a contrast range that can easily be captured by the camera’s sensor, or adjusted in post-processing when shooting in Camera RAW mode. After all, that is one of the many advantages of shooting in the RAW file format as opposed to jpeg. Despite criticism from some members of the photography community who take issue with any artistic interpretation of images – especially the highly saturated, over-the-top, surrealistic processing techniques (the so-called ‘Harry Potter’ look) employed by some photographers inexperienced in the use of HDR software – high dynamic range imaging has indeed found its rightful place in today’s digital world and truly brings out all of the organic tones, textures, details and colors inherent in high contrast subject matter when properly utilized. After all, photography is an art form open to interpretation. I spent many years laboring in the darkroom in an effort to achieve prints with excellent dynamic range, the goal of every good photographer and printmaker. Thankfully with HDR technology, I can now achieve my photographic vision in difficult lighting situations when necessary.
For complete start-to-finish tutorials on HDR photography, color management, merging files to HDR, post-processing, and fine art (inkjet) printing, please read my three technical articles on Breathing Color’s The Art of Printmaking guest blog. These three articles can be accessed from my home page (or any blog page) at the top of the right sidebar, or click here for my blog post about these HDR photography and printing tutorials.
Advantages of HDR Photography
- Overcomes classic dilemma of whether to expose (meter) for the highlights or shadows; HDR captures it all, from the deepest shadows to the brightest highlights
- Greatly enhanced tonal range; very rich details and textures in images
- Huge color gamut vs. low dynamic range jpegs; high-definition, 3-D look and feel; simply stunning prints
- Remarkable tones, colors, and life-like textures never before possible
- No need for additional artificial lighting equipment; shoot from inside the cave to outside its mouth and still see every detail
- Shoot in harsh light with success; shoot any time of the day or night
- Capture the scene as your eyes see it – without compromise
- Viewer/buyer sees image as you experienced it, rich with emotion and in proper context
Great Subject Matter for HDR Photography
- Landscapes with high contrast and lots of clouds; be forewarned that bald (cloudless) skies will generate more image noise
- Dimly lit interiors such as churches, theaters, bars, homes, etc.
- Metal, chrome, and machinery such as old trains, cars, trucks, planes, or industrial equipment
- UrbEx (urban exploration) or RurEx (rural exploration) – photography of abandoned and decaying structures and the objects within them
- Vintage, old, antique, and nostalgic subjects such as those found in ghost towns; the painterly look works well here when making post-processing decisions
- Twilight time or low light situations (no, not vampires – sorry, Edward)
- Interiors with window views; great for Architectural Digest type images such as the interior of a cathedral with window views out to the sky (very dark to very bright)
- Two rooms with a connecting view where you can see from one room into another, or rooms connected by a hallway
- Texture-rich subjects such as walls with chipped and peeling paint and rusty crusty objects; note that HDR amplifies textures and cloud formations
Minus Tide at the Beach During Sunset – The Before and After
Below are examples of a before-and after-HDR image taken at the beach during sunset and a minus (unusually low) tide in Shell Beach, California. The first image below (an original, non-processed Camera RAW file) shows the camera’s attempt at averaging light over the entire scene. As you can see, it does a very bad job as both the highlights in the bright colorful sunset and the shadow details in the foreground (showing the rocks and tide pools) are completely lost. The sunset has been overexposed, and the water, tide pools, rocks and bluffs underexposed. My, what a compelling image! :–((
Now, enter the fabulous technology of HDR photography. The image below shows proper exposure in all areas across the entire scene, from very dark to very light, without compromise. Just as my eyes saw it. This second image is a composite of nine separate bracketed RAW shots processed in HDRsoft’s Photomatix Pro, my favorite HDR processing software. These nine shots range from 4 stops underexposed to normal to four stops overexposed. After merging the nine images together and tonemapping them in Photomatix Pro, the merged file was further processed in Adobe Lightroom, Photoshop, and with onOne Software’s Perfect Photo Suite. What a difference HDR makes!