From the beginning, photography has always involved an inherent frustration. Our eyes can see an incredible range, from details in the darkest shadows to rich colors in sunlit patches—film has never even come close to recording this range. Nail the highlights, and shadow areas often turn featureless black. Expose the deep shadow detail, and say goodbye to the lighter third of the image.
As he formulated his Zone system, Ansel Adams used special development to extend the contrast range of his negatives. Years later, Galen Rowell solved the same problem with split-neutral-density filters, pushing the technique to new limits. And with the advent of digital photography, photographers have discovered that they can combine two images of a scene (one exposed for the highlight, one for the shadows) into one perfectly exposed image using the computer.
Lately, I've worked out an interesting new variation on that digital technique by combining two different versions of the same image in Photoshop in order to expand the contrast range. Only now, thanks to the ability to shoot RAW digital files, can I obtain these two versions of the image with just one click of the shutter.
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