Photos show excellent dynamic range, with no visible clipping in the highlights or shadows (of correct exposures). Though they definitely fall within an acceptable range, automatic white balance under artificial lights tends to be rather warm, and even manual white-balance shots measure a tad green-heavy. Automatically balanced sunlit shots render slightly cool.
With the exception of certain types of spot-metering cases, all of the metering schemes delivered excellent, balanced exposures. The 40D's ISO sensitivity goes up to ISO 3,200 and remains visually unobtrusive as high as ISO 800. Beyond that, you can spot noise, but it doesn't jump out of the shadows and thump you in the face.
For Canon devotees, the EOS 40D is a great camera and remains an excellent choice compared to most of the dSLRs in and around its price class -- with one exception. Despite its many attractions, the Canon EOS 40D doesn't clearly outshine the Nikon D80, which costs a lot less. Though the 40D has the obvious advantage for action shooting -- almost double the burst rate and a higher top shutter speed -- the D80 generally feels faster and more responsive for single-shot photography.
We think the 40D ultimately does deliver better photo quality, but some people might find the differences more subtle than the price differential warrants. And, of course, the more expensive Nikon D300 remains a wild card until we've tested it. So for the moment, the 40D gets a hearty, if not wholly unqualified, endorsement.
Additional editing by Nick Hide