Joe McNally is one of my favorite photographers of all time, and he has a slightly different twist to gripping the camera, which is especially useful when taking pictures using a slow shutter speed – allowing you to regain one or possible two stops when shooting.
Even the most modern camera bodies and fastest lenses will experience a lack of light at some point. Perhaps you just want a slow shutter to help create a sense of movement or flow in your shot. Whatever the reason – this is a handy tip. Unfortunately, since Joe is left-eyed, the trick doesn’t work quite as well for right-eyed folks (like me) – but like Joe says, there are elements that even we can take from this.