Well I post this in response to some posting on using a single RAW, manipulate the levels, obtain 2 more sets of over and under exposed images and treated the 3 of them using HDR formula.
I personally find this rather silly because RAW only means more information retained and without compression, would means you get pixel to pixel colour values of 1 single snap and does not means you capture the highlights or shadow which may be over or under exposed
True enough recover highlight for those areas that are not totally washed out and recover shadow for those areas which are not totally saturated at zero. But manipulating the level is not going to make wash you values back to their correct values nor the shadow area.
Think about this. I colour an area 50% gray. then I perform level manipulation to produce 75% gray and 25% gray, does it means I succeed in recovering wash out or shadow areas ? It's just a mathematical formula to create an image, but capture an image. Obvious enough is one is just trying to fake for the sake of doing so.
HDR is about tackling the deficiency of linear sensitivity nature of the sensor or film as oppose to the non-linear vision that our eyes can offer us. Using multiple images overly exposed to recover shadow details and under exposed to recover wash out highlights.
If one bend of creating HDR for the sake of doing so, perhaps a direction is make your original image looks nicer.
Just my 2 cents worth.