Originally posted by Regalo First is for the built in HDR mode, how do I adjust range of sensitivity between the 3 shots?
You don't have a whole lot of control. There's basically two levels, 'Standard', and 'Strong'. Standard is relatively mild, could be used in relatively ordinary high-contrast situations to extend range. 'Strong' starts looking a bit more surreal with more obvious artifacts. If you want more control than that, or the benefits of RAW, then you'll need to do your own bracketing and HDR during post-processing.
The others have it right with the missing ISO 100--this gets disabled when you have highlight correction turned on.