High Dynamic Range – A start

I friend of mine introduced me to HDR (High Dynamic Range) photography. It’s interesting while at the same time being a new challenge in itself. The challenge is that you combine a number of pictures into one. This is typically done using the cameras multi-bracketing feature.

That means that the camera is instructed to make several exposures using various exposure compensations. A typical scenario would be to have the camera set to +-2 EV using three brackets.

That will result in 3 pictures being taken. One with normal exposure, one with +2 EV exposure (over exposed) and last one with -2 EV exposure (under exposed). When these pictures are combined a total image is composed which much higher dynamic range – that means high detail in both the dark and light areas.

During normal, single exposure photography, one has to choose which area to focus on or rather, to prioritize in terms of lightning. Depending on the camera this may have different names and different algorithms. In some modes an average is used and in other modes a single spot is chosen. In all cases though, the camera is not able to achieve the same dynamics that the human eye can handle. A common example is taking a picture indoor on a sunny day. The human eye has no problem in seeing both the interior of the room together with what is seen through a window from the outside. This can typically never be done with a normal camera with a single picture. You have to choose either to make the room look good (with the exterior being just a white spot) or the exterior to look good (with the interior of the room in more or less darkness).

Going back to the challenges of HDR. We have now taken the pictures and merged them together and should now have the same dynamic range (or better) than our eyes have. Unfortunately the computer displays as well as the printers we use also have a limited dynamic range. So in order to show the HDR picture we now have to compress the range into something that can be displayed or printed. If we just squeezed it back together without any hint of what we want to prioritize then we’re back where we started. Instead there are different approaches which lead to a more or less natural look. Depending on your taste you may find the result to be everywhere from ugly, surrealistic to really nice.

I tend to use HDR in a number of different areas – all quite different goals. I encourage you to try this for yourself and find your own favorite subjects.

All of these pictures and more can be found in my photo galleries at http://reveman.smugmug.com/

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