Hi Chris,
The Noise Reduction setting shouldn't have any influence unless you expose for 1/2 second and longer.
I've also loaded the sReala curve into my D70 to see how it works. Today I gave it some test shots, comparing between:
1. sReala curve loaded
2. Tone comp set to Normal
3. Tone comp set to lowest
4. Tone comp set to Medium+ (I don't remember the setting, as I haven't got the camera next to me)
The histogram is quite interesting - it shows significant differences between shots using the curve and shots with other settings. I haven't been able to explore the results in detail, but one conclusion I can make:
Setting no. 3 gives the least shadows at the extreme end (well, this is rather expected, I guess). This would be the best for post-processing, as nearly no detail is lost (particularly not in the shadow area).
However, the sReala curve does give a very nice rendering out of the box, but with less shadow detail. This could explain the higher noise you see, as noise affects primarily shadows.
I'm actually most curious to see if there are ways to restore a linear or "normal" tone curve in NC after using either the sReala curve or one of the settings. In other words, is the RAW data being influenced by the tone curve settings, producing different results/pictures with different Tone Comp settings?
If anyone has an answer to this, I'd be most happy to hear.