What (the fuck) is HDR?

A few years back, I was standing in a rock bar in Ibiza (the Pinguin Bar, but that's another story) chatting to a friend of a friend about photography. He introduced me to the concept of HDR over a few beers, so I went back home and did some learning.

There are many places where you can read about how HDR works, but this is the quick and dirty answer. Cameras can't see as well as the human eye (which is pretty shit hot when it comes to seeing stuff) - a great example of this is during F1 (Grand Prix? Motorsport? Oh, nevermind...) where a car goes through a tunnel - as the end of the tunnel approaches all you can see is a huge white light. Now, when I drive my car through a tunnel and out the other side I don't have this problem, as my eyes kick the camera's arse at this.

Let's look at some real life examples. I've taken a photograph here, normally exposed (according to my camera, anyway) with no special treatment, except I used a tripod. Take a good look - nothing spectacular, all the clouds are kinda merging into one, the lamp post in the foreground is one big black blob, and the trees on the left are kinda boring looking.

All in all, fail. But what would happen if the camera saw more like our eyes?

Let me show you the two other photos I took. Identical photos except for one, small change - I underexposed one, and overexposed another. See the underexposed one pulls out some amazing detail in the clouds that were all bunched up before? Love it. Everything else here turns into a silhouette.

Now check out the overexposed one. The clouds? Totally gone. But look under the bridge, and how all this lovely detail appears on the lamp post? Now we are seeing (across three images) more like what the human eye can see. And it's better. Lots better.

Now you need to check out the key to all of this - a piece of software called Photomatix. It takes your series of photos and combines them in an amazing, inexplicable way (bordering on Voodoo if you ask me) to produce one pretty fascinating image... See how all the best bits of the three, individual images have been combined to make this one image? To me, THIS is what my eyes saw that day, nothing like the first, correctly exposed image at all.

So, what the fuck is HDR? High Dynamic Range. Taking details from the darkest areas of the photo and combining them with the lightest areas of the photos. There's enough websites to find out if your camera can take three photos in a row like this, it's call AEB, (Auto Exposure Bracketing) and does it all for you. I would encourage you to download Photomatix, there is a free version that watermarks the end result, and it's pretty cheap to buy if you are interested.