http://www.nikonchat.com/nikon-digital-hd/
How do I create a high definition image with a digital camera?
I have a Nikon D80 and see people calling images or images HD HDDR and wondered how. I think it might be by adopting the multiple exposures and image overlay, but I was wondering if anyone knew in detail.
You are talking about High Dynamic Range. I know some newer DSLR cameras are incorporating this feature now. All that basically does is protect against the most prominent "extinction" due to overexposure, something that is very easy to do with digital. I can only speak from what I read, but I think you can configure the camera to take multiple exposures of the same scene and the camera create a proper exposure of both bright and dark areas. This is also commonly done by taking a picture of a scene to expose for the shadows, and by a shot and exposure of the highlights, then combining them in Photoshop and use layer mask to create a proper exposure. I know that the new version Photoshop CS3 has a function of high definition range where you can input multiple photos of the same scene and balance will automatically create a photo exhibition .. a high dynamic range photo. Hope that makes sense! 
Steve http://www.pbase.com/s_parrott
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