Digital needs to be treated like slide film in that you need to avoid overexposure. Once the signal on a given pixel reaches 255 there no longer is any information. Same as when a piece of film is overexposed.
For this reason learning to read the histogram is a vital aspect of technique. If you don't utilize the right hand side of the histogram to the greatest extent possible you're throwing away dynamic range.
This means shooting in RAW mode and adjusting exposure so that little except specular highlights are overexposed. The shot will not look its best until you normalize it in the RAW converter, but you'll often gain as much as a stop or two extra dynamic range by doing this.
The rest depends on ones tolerence for noise in the shadows and the ISO used. Of course it also depends on the camera model.
Overall I'd say that a properly exposed and processed RAW image has a bit more dynamic range that transparency film and a bit less than colour negative. But, if you use various techniques and tools that are fairly easy to apply you can get shadow detail and extended dynamic range equal to that of neg film. It just takes a bit more work in post processing. On the other hand doing this is faster than scanning. ::
Michael
