Is this a bug with ColorFunctionScaling?

Question

Is this a bug with ColorFunctionScaling?

When I try to supply my own ColorFunction Mathematica seems to partially ignore it, and the white color "burns through" if the function is too "sharp":

mycf[z_] := RGBColor[z, 0, 0]

GraphicsRow[
  {DensityPlot[(Sin[x] Sin[y])^4, {x, 0, Pi}, {y, 0, Pi},
    ColorFunction -> mycf, ColorFunctionScaling -> False],
   DensityPlot[(Sin[x] Sin[y])^5, {x, 0, Pi}, {y, 0, Pi}, 
    ColorFunction -> mycf, ColorFunctionScaling -> False]}
]

Answer 1

DensityPlot[] was automatically cutting off your function at the peak. To fix this, add the option PlotRange -> All:

DensityPlot[(Sin[x] Sin[y])^5, {x, 0, Pi}, {y, 0, Pi}, 
            ColorFunction -> mycf, ColorFunctionScaling -> False, PlotRange -> All]