Photoshop CS5: The Missing Manual

Creating High Dynamic Range Images

Once you get used to peeking at your histograms (Using Levels), you'll notice that very few images exploit the full range of brightness values from light to dark. More often than not you'll have more info on one end of the histogram than the other, meaning the highlights or shadows look really good, but rarely both. That's because digital cameras can collect only so much data in a single shot. If you've got a scene with both light and dark areas—like a black cat on a light background—you have to choose which area to expose for: the cat or the background. To capture more info, you can shoot multiple versions of the same shot at different exposures values (called EV) by varying your shutter speed, and then combine them later in Photoshop into what's known as a High Dynamic Range (HDR) image.

Using Merge to HDR Pro

In Photoshop CS5, Adobe put a lot of effort into making it easier for mere mortals to create HDR images. But before you get started, you need to dig out your camera's owner's manual and hunt for a feature called auto-bracketing, which makes your camera take a series of shots with different exposure settings by varying its shutter speed (better yet, set the exposure differences up yourself manually—see your camera's manual to learn how). Bracketing lets you tell your camera how many shots to take (use a minimum of three, though the more the better) and how much of an exposure difference you want between each one (pick two if you have the choice). ...