HDR and Moving Elements...
As many of us know, cameras today (at least as of this post) can only capture so much dynamic range per exposure and we use various HDR techniques to get around this limitation to get as close as possible to what the human eye actually sees. HDR is meant for static scenes since the merge process relies heavily on the alignment of multiple exposures at the pixel level to give us the added dynamic range we want.
To that end, what happens when we get movement in between the exposure frames when we merge our files for HDR? We get what is known as "ghosting" in our HDR output and this issue can be eliminated in many different ways. Current HDR software out today such as Photomatix and HDR Efex Pro have "de-ghosting" tools that you can use to eliminate the ghosting in your HDR in the event that there is movement in between your frames. Another aproach is to simply grab a frame from your bracketed set and in Photoshop, "mask out" any movement.
In the photo you see here, I decided to experiment a little bit and shoot my (7) bracket set from -3 to +3 since their was an incredible amount of dynamic range in the scene and wanted to ensure that I grabbed the detail from the shadows while preserving the highlights. After I had taken my bracketed set, I sat and waited for people to walk by and when people walked by, I took multiple shots with a shutter speed fast enough to freeze the movement. This was not a busy sidewalk by any means so it took me a bit before I had enough "walking shots".
When I came home and processed my HDR, I simply grabbed the frames that had people in them and just masked them into my HDR. It was a really simple process which in turn, made for an interesting photo.