I'm trying to figure out why my raster function hillshade has a noticeably more coarse texture than a hillshade produced by the Spatial Analyst tool. In the image below, the image service with a raster function and the hillshades stored as files all have no contrast stretch and display using bilinear interpolation. The same azimuth and altitude parameters (defaults) were used to produce the hillshades. Also, a temporary raster produced by a hillshade raster function returns better results than the raster function I've saved and applied to my image service. Why the difference in appearance?