Everyone of us has taken pictures and sometimes we stumble upon difficulties in capturing a particular image, especially those that involve great contrast differences, The classic example of taking a photo through a window, for instance. If we want to capture what's going on outside, the entire room becomes dark, whereas if we want the room to be well lit, the exterior explodes into light.
This behaviour comes from the fact that photo-sensitive materials don't have the amazing capacity of the the human eye and are, consequently, only able to comprise a small range of contrasts. The photographer is then forced to choose the area he wants to focus the photographic composition on, which stays within the limits of the material's light-capturing ability. It's the classic problem in photography and there are several ways around it that are able to produce amazing images.
Still, wouldn't it be amazing if we could have the ability of the human eye and were able to capture everything? The high lights, the shadows, every detail that makes a landscape truly emotional and spectacular?
That's where HDR (High Dynamic Range) comes in. It's a technique which, through photographs of a range of exposures between light and dark areas of a scene, can create a middle image, or equalized, from two distinct images. The result is a picture that has a wide range of exposure and reveals every detail from both images.
The software used to apply this technique is relatively common and is already available to whoever has Photoshop. To use it, you only need two identical images, one exposed to shadows, the other to light. The program will combine both to create the middle image.
To spike up your interest in this technique, here are some truly impressive pictures, created using the HDR technique. They can all be found at Flickr. Click for full size image.