High Dynamic Range images

"HDR 101":
Sometimes the range of brightness in a scene being photographed - from the brightest highlights to the darkest shadows - exceeds the capacity of what the camera (digital sensor or film) can capture in a single image.  In this case, the best compromise with a single exposure will exhibit blown-out highlights, and/or details in the shadows that are completely lost.  HDR image processing is the process of taking a set of exposures that collectively capture the entire dynamic range of the scene, and blending them into a single image (nowadays, usually with software).

These photo's were done with Photomatix using the "Details Enhancement" mode (aka local contrast enhancement).  It seems that an inevitable result of this particular HDR compression algorithm is what is called a violation of the global tonal hierarchy.  In other words, the brightness of some elements of the scene must necessarily be made more or less bright, relative to other elements in the scene, compared to how they appear live.  If that is pushed to an extreme, the photo takes on a more "surreal" look which almost has the appearance of being painted rather than being a photograph.  I've experimented with different levels of this - some of these shots look fairly realistic, some look painted.  Sometimes it works, sometimes not so much - you decide.