The Canon EOS 40D digital SLR camera's self-timer feature allows you to take a picture using a 10-second or two-second timer. The 10-second timer makes it possible for you to position yourself quickly into a shot. The two-second timer makes it possible for you to remove your finger from the shutter and move away from the camera to prevent camera shake caused by touching it. No matter which timer you use, setting the self-timer feature only requires that you know which button to push to access the self-timer options. The rest simply involves focusing and taking the shot.
Turn on your Canon EOS 40D digital SLR camera.
Press the "AF/Drive" button.
Look at the camera display and turn the "Quick Control" dial to the 10-second self-timer icon or the two-second self-timer icon.
Position your camera on its tripod to face your subject. Focus on the subject and then push the "Shutter" button down to start the self-timer.
If want to use the timer with yourself in the picture, focus on the area where you're going to position yourself, and push the shutter button part way to lock the focus. Set the Focus Lock feature and then push the shutter button the entire way. If you hear the beep increase after setting the self-timer, the camera is about to take the shot and the timer countdown on the display has nearly ended.
Do not stand in front of the camera when you push the shutter button. Standing in front of the camera can cause the camera to automatically refocus to the place where you are standing.