Originally Posted by
Steve Smith
Hi Don,
HDR stands for "high dynamic range" - it is designed to produce a higher dynamic range than you can get from a single frame. I chose HDR for this scene for the same reason that Real Estate Agents use HDR to show the interior of a house and the view through the windows in a single image. I wanted to get a dynamic range that included the relatively light sky and the relatively dark land as visible entities in a single image. A single frame could only get one or the other - the sky or the land but not both and could not possibly achieve a higher dynamic range than a blended HDR image. As proof of this, the histogram from the blended image is far superior to any histogram from one of my single frames.
I chose ISO 800 because of the very low light conditions. ISO 100 here would have given an excellent image of a black screen. Roger Clark at clarkvision.com has some very interesting articles about the meaning of exposure and ISO in digital cameras that are well worth reading.
Steve Smith