I was shooting a baseball game to practice. I used a prime lens with fixed aperture (av) and autofocus. I pointed the lens at the batter a then try not to move the camera and watch the pitcher send the ball to get the batter trying to strike the ball.
Doing that many time I figured I could kinda unfocus my two eyes, the left one was watching into the viewfinder and the right one was watching the real world. This way I could synchronise and frame the batter and the catcher while I was watching the pitcher. It was a bit astraying for the eyes, but it sure was cool, it felt robotic, with the autofocus red square flashing in the 40d viewfinder.
Anyhow, I just wanted to share this trick and know if it's has a common name where I could get more information about it.