Well I heard that only the "1" series cameras from Canon have an accurate counter. After all PM reads whatever it finds in the EXIF data in the photo. I am sure all of their cameras have a hidden counter stored in the non-volative memory onboard the camera, but usually this is accessible only trough service software communicating directly with the camera (that was the case with Nikon cameras, although their EXIF counter worked well). At least when I talked with NPS about some nikons they told me there are logs stored in the camera of all errors and similar things, accessible by them (incidentally, the log didn't have the intermittent shutter error I have had few years ago with D70, so I had a harder time getting a replacement from them :-( ). I guess the Canons have some internal memory for this as well. Not much good answer to your question, but that's all I know
Frantisek
