I've recently learned a great trick for getting natural HDR results for virtual tours without a lot of extra work.
If you have a camera that generates RAW files, your camera is already capturing much more exposure information than a typical JPEG can handle. Most RAW files store 12 bits per pixel, and some newer ones are 14-bit. A 12-bit file has 16x more information than a JPEG, and a14-bit file has 64x more information.
Coupled with good HDR software, a single RAW file can be converted into multiple "simulated" exposures and you can output a nice, natural-looking tonemapped picture from a single shot.
While it's true that you will get even more dynamic range from multiple exposures, this only really matters if the light range of the scene is extreme. There are two other big advantages of the single-RAW workflow: since it's only one exposure, you never have issues with ghosting due to wind, clouds, or other moving objects between shots. Secondly, the workflow is very simple since it's just one shot!
Here's a sample I worked on tonight:
The first example was done with Photomatix
software, which is available for Mac and Windows and is reasonably priced at $99. There is also an open-source application that can do the same thing, called QTPFSGUI
. The second example was done with QTFSPGui.
In Photomatix, to get started you just "Open" the RAW file and wait. It will generate the "pseudo-HDR" file and allow you to apply tonemapping. Photomatix also has a nice noise-reduction filter which is very useful for shadow details on some camera.
In QTPFSGUI, you just do "New hdr,"choose the RAW file, and hit "Next" then "Finish." Click "Tonemap the HDR" and play with settings as you like. There are a bunch of different tonemapping algorithms listed by their creators. The "Reinhard '05" and "Mantiuk" options seemed to do a nice job with the samples I tried. All of the algorithms have adjustments.
Photomatix has a Batch Processing mode, although I am not sure if it can work with this workflow.
All in all, this process offers a very low-cost, fast way to improve your images that I think is perfect for images bound for TourBuzz!