I've recently been in a very strange discussion about what does and what does not constitute HDR imaging. It was strange because the definition used by the other party in no way took note of what HDR actually stands for. Thought I'd knock together a quick post to detail what is, and what isn't, HDR. HDR stands for High Dynamic Range. The dynamic range of an image is the difference in luminance between the brightest and darkest parts of the image. The luminance range is referred to in EV (Exposure Values) which are equal, in photography terms, to one F stop of aperture, doubling or halving the shutter speed, or doubling or halving the ISO value. In order words, increasing or decreasing by 1EV is the same as doubling or halving the amount of light. Many cameras now support a dynamic range of 11 EV. That is, the difference in brightness between the darkest and brightest things the camera can "see" works out as 2 11 times as much light. Anything too dark for a pa...