How to Reset a Canon 40D to Factory Settings
The Canon EOS 40D digital camera features a wide range of settings and various photo enhancement options so you can get the most out of your pictures. Adjust autofocus options, image quality, contrast, sharpness, white balance and other options. You can also reset these settings back to the default configuration when needed.
Open the "Tools" tab.
Navigate to the "Clear All Camera Settings" option. Press the "Set" button to select it. A confirmation prompt will appear on the screen.
Turn the navigation dial to highlight "OK," then press the "Set" button to make the selection.