How can RAW help recovery highlight detail?
It depends. I have Bruce Frazers excelent book Real World Camera Raw, which I can strongly recommend to anyone use Adobe Raw Converter. In that he says (pp35 for anyone who has the book) If the particular pixel is clipped to white in all three channels (R/G/B) then there is no highlight detail to recover. If however a single channel (or better two) still contain some information, ACR will do its best to recover detail.
He goes on to say, in practice most camera will let you recover 1/4 stop of data/detail and some up to 1 stop. Also (at this goes against conventional digital expose wisdom) while he doesnt advocate deliberate over exposure, if you are shooting in changing lighting conditions, the linear nature of digital capture (
http://www.luminous-landscape.com/tu...se-right.shtml shows that 50% of your data is in the brighest 1/5th of the image) makes it preferable to err on the side of
slight overexposure rather than underexposure, because underexposure will make your shaddows noiser tahn they need be. In these situation he says ACR highlight recovery provides a usefull safety net.
In the case of your flower Rob, it looks as though all 3 channels have burnt out completely