So I've ran into a fairly serious problem with the Luma and RGB Color Corrector plugins in Premiere. The whole tonal range shadow-midtone-highlight division thing has gone whacky. The strangest part is that this feature works great as a part of the fast and 3-way color corrector plugins, just not the Luma and RGB.
Pictures speak a thousand words so here is what I am talking about. Normal looking tonal range preview from the 3-way color corrector:
RGB Color Corrector Tonal range, note the inverted transition areas from shadow to midtone:
If I use a large transition from shadows to midtones, it gets really whacky, and doesn't even render the shadows as black anymore:
And to show that this affects the final product, here's what the composite looks like if I, say, brighten the shadows:
I'm working with 5DmkII footage on 64-bit windows 7. I've tried to eliminate all possibilities and have tried a blank project with a single PSD file imported and applied the plugins and get the same result. Strange to me that I haven't been able to Google anything on the subject...