From Dpreview:\n\nIt appears that Canon has reached the limit of what is sensible, in\nterms of megapixels on an APS-C sensor. At a pixel density of 4.5 MP/\ncm² (40D: 3.1 MP/cm², 1Ds MkIII: 2.4 MP/cm²) the lens becomes the\nlimiting factor. Even the sharpest primes at optimal apertures cannot\n(at least away from the center of the frame) satisfy the 15.1\nmegapixel sensors hunger for resolution. Considering the disadvantages\nthat come with higher pixel densities such as diffraction issues,\nincreased sensitivity towards camera shake, reduced dynamic range,\nreduced high ISO performance and the need to store, move and process\nlarger amounts of data, one could be forgiven for coming to the\nconclusion that at this point the megapixel race should probably stop.\nOne consequence of this is that the 50% increase in pixel count over\nthe 40D results in only a marginal amount of extra detail.\n\nWe're by no means saying the 50Ds image quality is bad but it's simply\nnot significantly better than the ten megapixel 40D. In some areas\nsuch as dynamic range and high ISO performance it's actually worse and\nthat simply makes you wonder if the EOS 50D could have been an (even)\nbetter camera if its sensor had a slightly more moderate resolution.\n\nThe EOS 50D has to stand its ground in a highly competitive bracket of\nthe DSLR market. It is currently almost 0 more expensive than the\n40D, almost 0 more expensive than the Nikon D90 and for an extra\n0 you can bag yourself a Nikon D300.