High Dynamic Range (HDR) is a technique used in photography to capture a greater dynamic range between the lightest and darkest areas of an image. When you take a photograph, your camera is capable of capturing a certain range of light, just like your eye is able to observe a certain range of contrast within a scene. If the scene you are trying to take a picture of has some really dark areas and some really bright areas, your camera may not be able to capture detail from both areas in one image. You, as the photographer, choose which is more important and set your exposure accordingly, losing detail in either the shadows or the highlights as a result.
One of the things you can do with HDR involves taking multiple images with different exposures to capture those details in both the lights and the darks. The specific technique photographers use to create an image that squishes these multiple exposures in to an image that can “fit” in to the functional dynamic range for viewing or printing is called tone mapping. Tone mapping is so synonymous with HDR that the terms are often used interchangeably, but HDR is a general term for the idea of capturing a wide range of contrast, and tone mapping is a technique for processing HDR images in to something practical.
To demonstrate, I took these images on a trip up to the mountains.
The composite above is of three separate images I took with different exposures of the same scene. In the center, the image captures a bit of detail in the clouds and some in the trees. Most likely, this image is what the camera would have produced by metering the scene, but it loses the drama from the clouds and the separation of the trees down the hill. The other two images come from the auto-bracketing feature of my camera, which captures the same scene at different exposures. On the left, the sky is blown out, but there is additional detail in the trees. On the right, the image captures the dramatic details in the clouds, but little detail from the trees.
Break Out The Pocket Protectors
Let’s say the center image captures 12 EV (exposure value, or stops) of light. That’s pretty good, considering our eyes can handle between 10 – 14 EV. But in addition to the center image, I had my camera take another image 2 stops below and another 2 stops above the exposure of the center image, which gives me an additional 4 EV of information, or 16 EV total. HDR!
Now that we have all that information, we need to do something useful with it. 16 EV is a higher dynamic range than my eyes can process, and much higher than the 10 EV of many monitors. The answer is: tone mapping. Tone mapping allows us to replace (or map) one set of colors for another in order to make all of those EV fit in to something our monitors can display and our eyes can see.
To do this, we need software.
There is an option to send selected images to Photoshop for HDR but, let’s face it, HDR in Photoshop doesn’t compare to the power and ease of use of Photomatix. And it just so happens that there is a Lightroom plugin included with Photmatix Pro that makes integration between the two a cinch.
You can download a trial of Photomatix from their website: http://www.hdrsoft.com/download.html. Install both the Photomatix Pro standalone application as well as the Lightroom plugin.
Creating A Tone Mapped Image With Lightroom and Photomatix
In Lightroom, select your bracketed images and click on File > Export or use the shortcut ⇧⌘E .
With the Photomatix Lightroom plugin installed, you have a new Export preset, shown below. The folks at Photomatix recommend leaving the color space as Adobe RGB for the best results.
Change any other options that you want and click on Export.
The next dialog that appears gives you some options for how Photomatix will align the images and a few other settings. I hand-held my camera when I took my shots and I found that the by matching features option worked better for my images, but mileage may vary. If you try one and your images don’t seem to be perfectly aligned, try the other option.
The other option this dialog presents is what to do with the final image. You can automatically re-import the final image back in to Lightroom, which is handy.
Click Export, and Lightroom will export the images to Photomatix.
Now, you’ll be in Photomatix. While Photomatix is extremely power and easy to use, there are a lot of different options. I recommend reading more about the tool in their documentation, but also just experiment with the options. The presets on the right will give you a good starting point covering many different styles. When you’re happy with your image and ready to head back to Lightroom, click the Save and Re-Import button on the left.
If you selected the option, Lightroom will have automatically imported the output file from Photomatix.
Now do any further adjustments that you want in Lightroom.
Lightroom and Photomatix make it easy to process your HDR files in to a beautiful, tone mapped image. With the Photomatix plugin for Lightroom, the integration is seamless! Try it out, and share your images with the Lightroom Fanatic community on Twitter by using the hashtag #lrfanatichdr!
Check out the video tutorial for this post below!