Practical HDR

Sooner or later, a photographer will run into the brick wall of the limitations of the digital camera sensor. Sensors today are very good, but they’re incapable of capturing the full range of tonality—from extreme shadow to bright highlights—that our eyes can see. While RAW capture provides greater flexibility in adjusting what’s captured, it’s still limited by the sensor’s capabilities. For the best exposures, we have to pay careful attention to what the camera can and can’t do with the light in a scene.

HDR, or high dynamic range, is a digital imaging technology that allows us to go beyond the limitations of our cameras and their sensors. With this technique, we can make pictures that are closer to what we actually saw with our eyes—photographs that represent the world in more realistic renditions that simply weren’t possible in the past, even with film.

There have been two directions with HDR photography: realistic and unrealistic (though imaginative) interpretations. In my work, I’ve been less interested in the unrealistic, more illustrative types of HDR. I’ve also found that many photographers are more interested in simply getting better images of the real world that they see around them; we’ll look at using HDR for this more practical purpose.

How HDR Works

With HDR, start by taking multiple exposures of the same scene—exposures that vary from underexposed to overexposed—then use software to combine the tonal information from that range of exposures into a single final image. This allows you to capture detail, color and tones and merge them into one image that couldn’t be captured by a single exposure.

This changes what a photographer can do with real-world scenes. You now can shoot a scene that has dark shadows and bright sunny clouds in the same composition and show off detail in both areas. This is more than simply fancy digital technology; it actually changes the way we as photographers can look at the world for our photography, and it gives us new opportunities for getting better pictures.

First Steps

To get started with HDR, you’ll need several exposures of the same scene. Each of these exposures must be framed identically or you’ll have problems assembling the final image.

Here are some ideas that I find work well for HDR shoots:
1. Shoot at least three photos, each with a difference of one or more ƒ-stops in exposure.

2. Use a sturdy tripod and lock down your camera on the scene.

3. Avoid shooting anything with movement, including wind blowing your subject around. (You can shoot moving water, such as a waterfall, although you can’t easily predict what the results will be.)


Merge multiple images into a perfect exposure.

4. Try using the auto-exposure bracketing function (AEB) on your camera. AEB allows you to shoot at least three exposures in a row with a variation in exposure for each. If you use your continuous shooting mode, you can shoot three pictures (or more) very quickly and keep your camera locked in position.

How Many and How Much?

In general, I try for a minimum of a one-stop difference between exposures, then use three to five exposures for the scene. Sometimes, I find that the results are great using three frames with a 1.5- to two-stop difference in exposure; other scenes seem to work better using five frames with aone-stop difference in exposure.

Since I frequently use AEB, this can be limited by what’s available for a given camera. For example, on my Olympus E-3, I can shoot only a one-stop difference at a time, so if I need a big range of exposures, I’ll use a five-exposure bracket. Yet on my Canon EOS 40D, I can shoot with bigger change, so I can try three exposures at 1.5 stops apart.

I wish I could give you specific information on what exposures would work in every situation, but “every situation” is different and will require you to modify your approach. However, with experience, you’ll start to know what seems to work best for the specific subjects that you like to photograph. Photographers who are doing less realistic work can try almost anything in the range of exposures.


LR/Enfuse


Into The Computer

Once you’ve captured your scene with multiple exposures, you need to upload them onto the computer and work on them with software that allows you to combine the pictures into a final HDR image. You don’t actually have to do a lot, other than open your series of exposures into the program. The software then automatically examines your exposures and puts them together into a final HDR shot.

Most of these programs also allow some adjustments as to how the exposures come together. Sometimes these adjustments can be done before you do the HDR conversion and almost always can be done afterward. A number of software programs allow you to do this.

Adobe Photoshop CS versions have an HDR capability, but I haven’t found it to be that useful. It’s just too hard to get good results. But if you have Photoshop, give it a try. Photoshop CS4 runs $699 (new) and $199 (upgrade).

Essential HDR is an easy program to use, and for me, it has created more natural results than Photomatix. I prefer it for nature photography and anything that needs a normal photographic look. Essential HDR costs $69 (Windows only).


Photomatix

LR/Enfuse is a blending software technically. That said, it yields HDR-type results directly from Lightroom (it’s a Lightroom plug-in). I like LR/Enfuse because it fits my Lightroom workflow quite well. It doesn’t produce results as strong as those from Essential HDR or Photomatix, but makes it easy to adjust photos in Lightroom before making the jump to Enfuse so you can optimize your results. The free trial version limits output size to 500 pixels. Make a donation of any amount on the website, and you’re given a registration code that removes the size restriction. All future updates are free.

Photomatix really jump-started HDR for photographers. It has excellent capabilities and is flexible in application, too, as it can be purchased as a stand-alone program, a plug-in for Photoshop, a plug-in for Aperture or an export plug-in for Lightroom. It seems to be the program of choice for photographers who want funkier results from HDR because it produces those effects quite easily. It’s available for Mac and PC for $99. Other HDR programs are entering the market, so you may find new ones work well for you, too.


Essential HDR


HDR Processing On Other Images

Most HDR programs will allow you to take a single image into that program and do some processing on it. This can create interesting results, especiall
y by pulling more detail out of dark areas. You won’t match a true HDR effect because there isn’t the same amount of total information in the picture, but it can be helpful on certain types of photographs.

Another way of using many HDR programs is to double-process RAW files. Take a single RAW image and process it twice, first to optimize the highlights (while ignoring what happens to the shadows) and again to optimize the dark areas (while ignoring what happens to the highlights). You can even triple-process an image, creating a third version that optimizes midtones only. Sometimes you find that any single processing of a RAW file is a compromise; this technique allows you to favor specific tones and colors by processing the same file two or three times. (This double-processing technique is described in more detail on my website at www.robsheppardphoto.com.)

Then put those processed RAW files together into a single file by using one of the HDR programs. This works very well with Lightroom and LR/Enfuse—you can create virtual copies of your image in Lightroom and do individual processing on each for specific tones, then output through LR/Enfuse.

HDR is changing the way we photograph, giving us new opportunities for capturing the world. We now can create images that more closely render our world and more truthfully communicate what we see.

Rob Sheppard’s Basic Lightroom Workflow outline is now available on his website, www.robsheppardphoto.com.

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