26. CREATING HDR IMAGES

AS WONDERFUL AS our cameras are, there are times when the camera will not be able to capture the entire range of light values in a scene with one single shot. If you try to expose for a beautiful background in a scene, chances are you’re going to underexpose the shot to get all of the saturated colors. When you do that, you’ll notice that the foreground elements, or anything that happens to be behind the light source, turn out really dark. If you try to expose for the foreground elements, you’re likely going to overexpose the sky, and you’ll lose all of the color you’re intending to capture in the picture.

In situations like this, the solution is to take a series of pictures at different exposures, and then merge the images together to create a single image with a higher dynamic range. Up until very recently, Lightroom did not have the capacity to do this, but now it has a built-in HDR feature that works extremely well for producing really natural-looking HDR images.

When Adobe released this update, they said that one of the benefits of working with HDR in Lightroom is that you need fewer images to create the resulting HDR file. After some experimentation with the HDR feature in Lightroom, I can safely say that they are correct. You can get away with using about three images of varying exposures to create the final HDR file.

Locate the three images you wish to use in the filmstrip below the main workspace or in the Grid View mode, and Command-click each image to select it. Right-click on one of the images and select Photo Merge > HDR from the menu (Figure 26.1).

Figure 26.1 Merging images to an HDR file in Lightroom.

A box will appear with a preview of an image that is the result of all three exposures merged together into one (Figure 26.2). You’ll notice two options here that are pretty important. The first option—Auto Align— allows you to compensate for any movement of the camera between exposures.

The Deghost Amount buttons will help you to compensate for any movement on the subject’s part—for example, maybe some trees were blowing in the wind or a person moved from one side of the picture to another. If any part of the scene moves during the bracketed exposure, it will cause ghosting in the picture. The amount of deghosting you choose will depend on how much movement occurred in between frames, and thus how much ghosting there is in the image.

Lightroom is able to merge the files to create an HDR preview pretty quickly because it uses the JPG images that are embedded in the RAW files to do so. In the preview window, you also have an option for Lightroom to Auto Tone the image. This simply adjusts your exposure values so that you can see a pretty good HDR file right out of the gate. Once you select Merge, Lightroom will merge the RAW files to create the finished HDR file, which is an actual RAW file in a DNG format. This means that you have the opportunity to adjust the temperature and tint of the HDR image as if it were an original RAW file.

You’ll also notice that you can now adjust the Exposure slider in a range from +10 to -10 (Figures 26.3 and 26.4). While this level of exposure is really poor in a picture, the benefit of this is that you can use adjustment brushes to bring in a lot more detail in the highlights and shadows than you could in one of the individual RAW exposures (Figure 26.5).

Here’s another tip I think is pretty cool: There are times when you would like to bypass the HDR preview window entirely. You know that you want to work with this picture when it’s completed, and you don’t want to stop in the middle to confirm the choices. Hold down the Shift key while you right-click one of the selected files, and then select Photo Merge > HDR. This will merge the files using something called Headless Mode, which skips the preview entirely and produces the HDR file.

In Lightroom, the production of the HDR happens in the background. If you were to try to produce an HDR image in Photoshop, the software would prevent you from doing any other work while it worked on producing the HDR file. In Lightroom, you can continue to work on other pictures until the HDR file is completed.

Figure 26.2 The HDR Merge Preview with alignment, toning, and ghosting options.

Figures 26.3–26.4 Take a look at the range you can get out of an HDR file in Lightroom.

Figure 26.5 The final HDR file with Toning and Adjustment Brush applied.

Figure 26.6 A single-shot, middle exposure.

Figure 26.7 The final HDR image.