High Dynamic Range (HDR) photography has exploded on the digital SLR scene in recent years, and has rapidly become not just a special-effect technique, but a practical tool for professional, architectural and interior photographers, and well as outdoor shooters. Pros and serious enthusiasts use it for three main reasons: 1) Greater detail in dark shadows and bright highlight areas means effective pictures can be produced in situations not otherwise possible; 2) It can save time and money setting up expensive lighting systems; 3) It can give professional photographers unique images that make clients especially pleased with their work.
HDR is not really a new concept. Famed landscape photographer Ansel Adams actually created black-and-white HDR images in the wet darkroom by burning and dodging a single image. The master also used different papers, filters and developing times to expand the dynamic range of a negative.
Today's digital SLR cameras can capture detail, and color that were only a dream to photographers back in the days of Ansel Adams. But straight out of the camera, images can appear to have limited ability to capture the broad dynamic range that commonly occurs in sun-lit conditions. However, using some of the techniques possible in today's electronic "darkroom", we can produce results that go well beyond what the camera's default settings produce. HDR techniques can greatly expand the dynamic range, or range of brightness that's captured with detail and texture, in a digital image.
This two-part series on HDR for the Canon Digital Learning Center will cover the basics of HDR.
Part I primarily discusses how you can expand the range of detail and brightness in a single image – without shooting multiple shots at different exposure settings. Without an HDR software program, Part I shows how to begin to get HDR-type results, using Adobe Camera Raw and Topaz Adjust. Part I also touches on what you need to take a series of images for knockout HDR images.
Part II covers taking multiple original exposures for true HDR images, and processing your images using a true HDR program, such as Photomatix and HDR Efex Pro. Canon Digital Photo Professional, the software that comes free with your digital SLR, is also covered.
Away we go with Part I.
Look at image 1 entitled "Raw Possessing" of the gallery. Believe it or not, the second image is the actual original file, as it came out of the camera. It underscores the power that's possible in expanding the range of detail in a single Raw image during Raw processing. While Canon's Digital Photo Professional software (sometimes abbreviated "DPP") is a great program and offers tremendous image quality, we're going to show you how some of the specialized tools in Adobe's Camera Raw software – a component of the Photoshop and Lightroom programs – can be used to dramatically expand the range of visible detail in an original RAW file
Shown in the gallery is a screen grab of the Adobe Camera Raw window upon opening the file. As you can see, I have highlighted the camera/lens used and the settings: ISO 100, f/22 @ 1/500th sec., 15mm fisheye lens.
Here's why this information is important:
- Noise can creep into HDR images, especially when you process multiple images and when you open up deep shadow areas. Knowing that, you should shoot at low ISO settings to minimize noise.
- If you want to get the starburst effect when shooting directly into the sun, you'll need to shoot at f/22. At f/5.6, the sun would be a blurry, white spot. Important: never look directly into the sun and always wear sunglasses when shooting toward the sun.
- The 1/500th of a sec. shutter was the result of the lighting conditions.
- Canon's 15mm f/2.8 fisheye lens, combined with the full-frame EOS 5D Mark II, produced the dramatic fisheye effect. Until now, a full-frame sensor was required to get the full fisheye effect with this lens on EOS cameras. But with the recently introduced Canon EF 8-15mm fisheye zoom lens, that broad, dramatic fisheye look is now possible with small-sensor cameras, such as the EOS Rebel series, EOS 7D, and so on.
You see two screen grabs in the gallery – the before and after setting in Adobe Camera Raw. The changes are highlighted here. The most important difference is the Fill Light setting. Boosting this setting from 0 to 81 opened up the shadow areas of the scene. Notice that there is no visible noise in those areas.
Notice that the Recovery slider was moved from 0 to 80. This brought back some of the detail around the sun, which was actually captured in the original file.
By opening up the shadows, the image lost some contrast. The remedy was to boost the Contrast slider.
As a final step, the Clarity was boosted, which is somewhat like sharpening a file, and then the Vibrance. By the way, here's the difference between Vibrance and Saturation: when you boost the Vibrance you are only boosting the saturation of the colors in a file that are not already saturated. When you boost the Saturation, you are boosting all the colors in a file.
Creating an HDR-like image, like the Pozos image, is not always possible, especially when you want to capture all the fine detail in a scene. This two-part series began with this image, to show you the light capturing capabilities of the sensor in the Canon 5D Mark II.
View a before-and-after example of expanding the dynamic range of a file from a Canon 5D Mark II in Adobe Camera Raw. Here's an important point of sharing these photos: don't delete a file if you think it looks less than perfect on your camera's LCD monitor. There is a lot of data there – data that you can rescue in the digital darkroom.
Sometimes, however, the range of brightness you're trying to incorporate into a final image is simply too great to be handled by RAW processing alone. This is an example of when taking multiple original shots at different exposure settings, for a true HDR image, was necessary to capture the entire dynamic range of the scene. Here is where true HDR software becomes the tool of choice. This picture was taken in the lobby of the Florida Hotel in Old Havana, Cuba. Camera info: Canon EOS 5D Mark II and Canon 15mm full-frame fish-eye lens.
As professional interior photographers know, the goal in a final HDR image is to reveal details in the shadows and to preserve detail in the highlight areas. Here, this goal was accomplished without the use of adding any lights. We'll discuss the photographic techniques and hardware used first, and then discuss how to bring several images of the same scene into a finished image with a broad tonal range, using HDR software.
The exposures for this setting were 0 EV ("normal" exposure), +2 EV, -2 EV, -3 EV and -4EV. ("EV" stands for Exposure Value; and each value refers to an f-stop – so +2 EV means the image was intentionally over-exposed by two stops.) Part II covers the number of exposures needed for HD images.
Okay, let's talk gear and camera settings. Gear first.
It is possible to take a series of images while hand-holding your camera – especially when you use a very wide-angle lens and fast shutter speed and hold your camera very steady or brace it on a support. Here is a hand-held HDR image, created from three exposures, taken at the 0 EV, +2 EV and -2 EV settings. This is actually a very practical time to use the high-speed continuous "drive" setting, if your camera offers it, combined with Automatic Exposure Bracketing.
However, for HDR photography, it's best to use a tripod. Yes, today's HDR programs do a good job of aligning a series of images, but if the images don't line up, you'll get a ghost image in your HDR image. Using a tripod, combined with using the Canon's self-timer or cable-release, is your best bet for having your images lined up.
When it comes to a tripod for HDR photography, a tripod with a ball head is recommended. With a ball head, you can quickly and easily adjust the camera to the exact, desired position. Also, because most HDR photography is wide-angle photography, you don't necessarily need a heavy-duty tripod.
Keeping your camera level is important in HDR photography. The EOS 7D and EOS 60D have a built-in electronic level display. If you are shooting with an SLR without this extremely handy feature, use an accessory bubble level, which mounts in the camera's hot shoe.
Again, HDR photography is mostly wide-angle photography – where the contrast range of a scene can be very wide. Recommended lenses include: 14mm, 15mm, and ultra-wide zooms like the 17-40mm lens (or EF-S 10-22mm zoom, for APS-C sensor cameras like the 7D or Rebel series).
Following is a look at some pictures taken with those lenses, as well as a few tips on why and how to use them, and the benefits of using these lenses.
Canon EF 15mm f/2.8 fisheye lens: This full-frame fisheye lens offers tremendous depth-of-field. The curvature (distortion) can add impact to a scene. However, the dramatic look the 15mm lens produces only occurs with full-frame SLR cameras, like the EOS 5D Mark II. The new Canon EF 8-15mm f/4L fisheye zoom lens allows the same ultra-wide, 180˚ diagonal fisheye coverage with smaller-sensor cameras, like the EOS 7D or 60D.
Canon EF 14mm f/2.8L II lens: This ultra-wide lens is called a rectilinear lens, meaning that it's designed to keep straight lines straight – unlike a fisheye lens. That extensive distortion correction comes at a price, which is significantly more than the 15mm lens. Again, the ultra-wide coverage demands a full-frame sensor in the camera body.
Canon EF 17-40mm f/4L lens: The zoom range of this lens is ideal for HDR photography, with full-frame cameras. Users of EOS models with smaller APS-C size sensors, such as the EOS 7D or Rebel models, can get the same coverage with the EF-S 10-22mm zoom lens. As with all lenses, make sure you use a lens hood to keep stray light off the front of your lens.
When it comes to camera and lens settings several things are important to remember:
- The aperture must remain the same for a series of images, which means shooting on either the Manual mode or Aperture Priority mode.
- Your focus must remain the same for a series of images, which means it's best to set the focus in the AF mode, and then switch the lens to the MF setting.
- When it comes to bracketing, you have two choices: Automatic (AEB) or manual bracketing. That will be covered in Part II.
- The number of shots and range of exposure adjustments are not always the same over and under EV. That will be covered in Part II.
Check back soon for more HDR must know info in Part II.
The CDLC contributors are compensated spokespersons and actual users of the Canon products that they promote.
All images are copyright Rick Sammon
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