High Dynamic Range Photography—What and Why

July 19, 2012 20:41 – 20:41

HDR stands for High Dynamic Range. There are great expositions and tutorials online, so I won’t reinvent those here. Basically, HDR is a technique that combines multiple differently-exposed photographs into a single photograph, allowing you to fit a much wider range of brightness, darkness, and colors into a single finished picture than might otherwise be possible.

I use a Canon 60D, which lets me automatically bracket three shots in succession. If I hold the camera steady and if nothing in the shot moves, then these three shots—one normal, one dark, and one light—are the input for the HDR photograph. I use something called Photomatix (not Photomatrix), which does the heavy lifting of combining/blending/fusing the pictures into one. Photomatix then gives me a variety of presets I can choose from. Or, I can play with the individual settings directly. I start with a preset, and if that doesn’t give me exactly what I’m looking for, then I play with the individual settings until a) I’m satisfied, or b) conclude that my idea for the picture can’t be done with what I have.

You’re not limited to three shots. I just go with those because my camera makes it easy. You could also go with just two. Or even with one. But, in the case of one, you’re using other features of the program, and what you’re doing isn’t HDR. It’s tone mapping.

It’s largely a matter of personal preference how much you do with the pictures. Sometimes, I want surreal and bizarre. Sometimes, I want just a little bit of enhancement because the original picture doesn’t quite show what I think is possible in a shot.

An example will probably help. Here’s a picture I took from my office window at about 8 this evening.

Not too bad. But, when I took the picture, I could still see trees and the roof across the street. Using auto-bracketing, my camera actually took the following three pictures in rapid succession:

As you can see, the roof is visible only in frame 3, but the cloud definition is missing. The clouds are present in frame 1, but you can’t see the trees, and most of the sunset redness is missing from the clouds. And frame 2 is so dark, all you can see is the colors of sunset in the clouds.

Using Photomatix, I then combined the three, and I settled for a preset called Fusion/Natural. I tried playing with the settings, but didn’t find a result I liked better than the final fused picture. Here, we get the best of all three pictures—sky, roof, trees, and clouds are all visible. And, unlike in some pictures, the results don’t look particularly “eerie.”

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