Crud from the camera body cap
Can you believe the crud coming off Canon’s body cap for the 1D Mark III? Somehow, a tiny part of the body cap shredded itself and the result was this crud inside the mirror box, released via a gentle shake. It’s a good reminder to check even such mundane items as body caps for integrity, and to always mount and unmount body caps and lenses with the camera facing down. A gentle shake released this crud (and more) from inside the mirror box:
