has anyone tried this cool technique w/ your pics?

 

wiki explains it all:

 

In computer graphics and photography, high dynamic range imaging (HDRI) is a set of techniques that allows a greater dynamic range of exposures (the range of values between light and dark areas) than normal digital imaging techniques. The intention of HDRI is to accurately represent the wide range of intensity levels found in real scenes ranging from direct sunlight to shadows.

 

HDRI was originally developed for use with purely computer-generated images. Later, methods were developed to produce a high dynamic range image from a set of photographs taken with a range of exposures. With the rising popularity of digital cameras and easy-to-use desktop software, the term "HDR" is now popularly used[1] to refer to the process of tone mapping together with bracketed exposures of normal digital images, giving the end result a high, often exaggerated dynamic range. This composite technique is different from, and generally of lower quality than, the production of an image from a single exposure of a sensor that has a native high dynamic range. Tone mapping is also used to display HDR images on devices with a low native dynamic range, such as a computer screen.

 

much more about it on the wiki link:

http://en.wikipedia.org/wiki/High_dynamic_range_imaging

 

some examples:

 

tower bridge in sacramento

 

times square at night

 

In short HDR is useful to the photographer because it allows a presentation of high contrast scenes in a way that our minds understand a scene, overcoming the limitations of film and digital capture.  Beyone that HDR enters the world of Dungeons & Dragons fantasy images that quickly get out of control. 

 

Color negative film and digital cameras can gather information from a 7 EV range, however they work in opposite ways because C-41 negatives can be over-exposed 5 EV's or more without blowing out the highlights whereas digital cameras blow out immediately like slide film.  However, they have the advantage of being able to bring up the shadows to a much greater extent than either color negative or slide film.  Slide film (positive film) is much more difficult to use than negative film because it gathers only a 5 EV range, which accounts for its high contrast, but also often loses shadow and/or highlight detail.  Black & white negatives also gather a roughly 7 EV range but do so in a way that's very forgiving of overexposure and underexposure, meaning a miscalculation of 2 or more EV's results in a printable image and a 1 EV miscalculation can usually be printed quite well.  The black & white zone system was a way that allowed high contrast (and low contrast) situations to be printed in a way that retained detail in the shadows and highlights.  This quality of black & white is part of the reason why it retains favor among the more hard-core fine art landscape photographers.

 

In short I find HDR most useful in place of a graduated neutral density filter for matching a sky with a landscape in a high contrast scene.  Even in very dim conditions, the sky is often more than 7 EV's brighter than what's below the horizon.  Here you can take one shot on a tripod and then another 3 stops lower for the sky, then merge them in Photoshop.  That's what I did for this shot:

 

HDR is easy to do, and along with Photoshop CS3's stitching software are the two biggest cliches taking over photography.  Hobbyist magazines are overflowing with HDR images.  CS3 also introduced an amazing "black & white" feature that allows color channels to be controlled in grayscale mode but so far people seem to have been slow to abuse that, maybe because the digital printing of black & white still stinks.