High Dynamic Range Imaging
By John Potter
HDR or High Dynamic Range images show a greater range of tonal detail than any given camera can capture in a single photo.
Frequently a photographer will shoot a photo three or more times with different exposure settings to ensure he or she gets the best possible image tonality in value range of darks to lights, color values, density of blacks etc. This method of shooting photos is called bracketing. Generally the photographer will choose the best exposure of the group and consider that the final image. Consider it the Goldie Locks approach.
HDR can take this method of shooting one step further. Rather than accepting the best choice of the group as the final product HDR software combines the elements (hopefully the best elements) of each image into one final image. Of course it helps if the photographs were taken with a tripod to ensure they match up and there is tweaking that can be done within the HDR software.
HDR can be particularly helpful in a scenario where you are shooting a photo indoors during the day with the blinds on the windows open. Before HDR a photographer would frequently have to choose between showing what was outside with the interior all being too dark or show what was inside with the windows showing as all white. There were, of course, labor intensive ways to get around it in the darkroom or later by manually combining different exposures of images in Photoshop, but it was still a pain. Now with HDR software it’s much easier.
The example I show above is a section of a larger image I recently shot. I needed to show the mosquito net hanging from the ceiling clearly as well as the rest of the room, but the netting was back lit by a window and was largely lost in the glow of the window in the best all around exposure I used. By bracketing and then using HDR software to combine the images I got all the detail I needed in the mosquito net and didn’t have to sacrifice the quality of the rest of the image. Notice that details from both the overexposed and overexposed images are retained in the final image. Some objects near the window cannot be seen at all in the two lighter photos, but are retained in the final HDR version.
Consider it the Goldie Locks takes everyone’s porridge and makes a fine pot of gumbo out of it approach.
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| Complete final product (for Flamingo Gardens) |
