Moire patterns in real-world images. Here are comparison
images by Dave Etchells of Imaging Resource using the Canon D60 (with an antialias
filter) and the Sigma SD-9 (which has no antialias filter). The bands below
the fur
in the image at right are the kinds of artifacts that appear in images when no
antialias filter is used. Sigma chose to eliminate the filter to get more sharpness, but
the resulting apparent detail may or may not reflect features in the image.