Thanks!
I made some stair-step curves to test posterizing. There are only 16 curve points available which limits the number of posterize colors to 8 or less steps but it's still fun. One of my other cameras has a posterize effect in it. I thought it would be fun to recreate that in my Canon. I attached some of my experiment curves to this post. Including the curve points files too so you can load them in the curve editor to see what the curve pattern looks like. I could make up to 8 stair-steps all the way to the corners with the 16 curve points available. If I tried balancing the shape, half of the points above the diagonal, half below the diagonal, by shifting the end points on the sides to make 90-degree bends. But then I lost too many shadows and highlights. You can see that pattern in the "poster.CV" file. "poster3" has 7 steps, "poster4" has 6 steps but is more balanced on the diagonal. Even so with the way they are it makes for some interesting "painted" effects.
I found that setting curves for the RGGB color is very different from setting one for RGB color. Darker tones quickly shift to purples because of both green channels being shifted darker. It would take a lot of experiments to figure out how to match the effect in RGGB. Maybe someday there will be an editor that can load a sample photo for instant feedback with finer control over the curve points. Custom curves would be easy to build that way.
Even so, this is still a fun and important feature to have just the way it is!
