Qtpfsgui has got to be one of the coolest applications I’ve seen in a while. It’s a free open source HDR (High Dynamic Range) imaging application that anyone can download and use for free. It’s similar in feature to Photomatix (very nice image samples here) which is a commercial HDR imaging application.
I played with Qtpfsqui by using my RAW images to fake the input sources by manipulating the F-Stop on the RAW images. Normally you need 3 photos with low, normal, and high exposure but I generated that from my RAW image taken back in 2006 by outputting -1.5, 0, and 1.5 F-Stops. It’s obviously not as nice as having 3 actual photos but it’s not easy to take a still from the same person 3 times without the object moving and most of the time you only have one RAW image. Obviously it’s also not possible to go back in time and retake the image.
So the bottom line is that you can bring out the shadows and the highlights of images at the same time and the results can look pretty stunning.