14 February 2005

High Dynamic Range photography

This may be the coolest thing I've found on the net today, and I don't know why I haven't stumbled across it beforehand. It's called HDR (High Dynamic Range) compression. In a nutshell, it enables a greater range of light to be displayed in a single photo.

It's particularly useful where photos have both light and dark areas. Normally to capture detail in the brighter parts of a scene you'd have to underexpose but then detail would be lost in the darker areas. Conversely, to get detail in the darker areas you'd have to overexpose but then the brighter areas are all washed out. With this technique you get the best of both worlds where both light and dark areas show detail. The only drawback is that you have to take multiple pictures of a scene at different exposures. This requires a tripod to avoid camera shake.

Hopefully image sensors in digital cameras will get to such a high sensitivity that you can use much faster shutter speeds to achieve the same exposure. For example, the longest exposing picture in the sequence that took 1/4 second today would only need 1/500th of a second sometime in the future. You could choose to take an HDR picture on your digital camera and it'd take a sequence of pictures all at different shutter speeds say in less than 1/100th of a second, meaning you wouldn't have to use a tripod. That'd be awesome.

Examples of HDR pictures can be found here. Since pictures speak 1000 words you'll probably understand what I mean a lot better by looking at them.

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