I'm really impressed with the new HDR feature in Camera Raw 9.0. It's easy to use and seems to do an excellent job. It is advertised as producing a 32-bit HDR image. This size would indicate that that is probable because my 12 MP NEF files are only 8 or 9 MB, and the resulting DNG HDR file is 56 MB. But both Bridge and Lightroom indicate that the HDR image is 16 bit. Any thoughts? I haven't yet tried it using Lightroom, but plan to do so shortly.
Jim, the result of the HDR merge is a floating-point DNG file. The image data itself is stored as 16-bit floating point data. When you render that data using the Camera Raw controls, we internally use a 32-bit floating point image processing pipeline to handle the rendering.