This was a particularly tough shot that highlights the differences between the D90 and the more expensive D300. The D90, like other entry-level dSLRs, tends to produce some color noise and have posterized areas in exposures like these. Similar shots I took with the D300 and other midrange cameras don't exhibit these sorts of artifacts. The upper inset is the original; the lower is brightened for easier onscreen viewing. (ISO Lo 1, 1/100, f5.6, 147mm equivalent, spot metering, sRGB)
Photo credit: Lori Grunin