Folks

It recently occurred to me that it should be perfectly possible to shoot HDR photos without actually shooting bracketed shots. Essentially, the idea is to create two or more additional shots based off the original RAW file with the requisite over or under-exposure.

My own particular HDR workflow uses both Aperture and HDR Efex PRo 2. When applying any sort of adjustment to a RAW image in Aperture (and I suspect Lightroom works the same way), Aperture "overlays" any changes to the original image in real-time. When considering RAW images, a change to the exposure should simply be altering those raw values thus, functionally and mathematically, there should be virtually no difference between a shot deliberately under or over-exposed in camera to one where you adjust the exposure value in post.

My own experimentation in this area suggests that this is actually the case and in evidence, I offer the two examples below. The first is composited from three shots done in camera, The second is created by taking the original normal exposure and the creating two versions—one under-exposed, the other over-exposed by the same amount as the original, in this case 1⅓ stops.

This means that it becomes possible to shoot stuff with rapidly moving objects like racing cars or aircraft in HDR—which would normally be impossible with conventional bracketed exposures— simply by manipulating the math. I have seen some discussion on other sites on this issue but, to me, it seems that they are not grasping what's happening to the underlying math when the manipulating the RAW file.

I would be most grateful for comments, gripes and whinges particularly those that indicate I am barking up the wrong tree.

=:~)