High Dynamic Range (HDR) is a exposure stacking technique that helps to extend the dynamic range in a finished image.
Dynamic range is the difference between the brightest spot in the image to the darkest spot in the image that you can see detail. Above that it is too bright and the highlights are “blown out”. Below that (darker) and the detail is lost in the shadows and simply becomes black to the eye and the printer. As Photographers we are always playing “tricks” with our images to get more out of them. In this case it is taking 3 to 5 images from under exposed to over exposed and combining those together in the digital dark room to blend the best parts of each image into the final image output.
There are a number of ways to do this. HDR specific software like HDR Efex Pro from NIK Software or Photomatix from HDRSoft give the digital artist an easy way to blend these series of exposures and offer a lot of preset “looks” as starting places. Photoshop from Adobe has an HDR blending function too. It also has an interesting 32bit way of processing HDR images that can extend the dynamic range even further. There are even ways to force an HDR “look” onto a single image by using extreme adjustment settings in Photoshop, Lightroom or whatever software you use to make adjustments to your images.
In general, when most folks think of HDR they think of highly saturated, contrasty images that border on surrealism and cartoons. While this is fun and even interesting on old cars and various other subjects, it is not what HDR is specifically about. It is simply a technique to extend dynamic range to the viewer of your finished image. What the photographer and digital artist does with this technique is up to them. I prefer to use it more subtly, to help support what I am trying to show the viewer. It helps me in those situations where a normal single expose just won’t cut the mustard and get me a shot worth working with.
It would take many posts to my blog or a very long article on a page to educate and cover this one subject: HDR. So I won’t do so here. I have linked some of the software and information above for you to do your own research. Perhaps over time I can cover specific areas of this interesting technique. For now I will simply share a few images that I did using HDR.