Making the Most of Long Exposure Handhelds
Did you know that there is a natural respiratory pause in everyone's breathing pattern? And that it happens every time you inhale and exhale? Yes. Every. Time.
Consider the trajectory (think “flight path”) of an object. You throw a baseball, shoot an arrow, or fire an (unguided) artillery round. What happens? It goes up, then comes down, and no matter how you do it, as long as the elevation stays the same for the initial and ending points of its flight, it will always follow a path that is perfectly symmetrical.
The star that is at the top of each flight path is called the "apex," or where the acceleration changes from positive (going up) to negative (coming down). It is at this exact spot that for a fraction of a second, the projectile has to completely stop all movement and is in that small fraction of a second just "suspended" in air completely immobile (even if you do it all very quickly and seemingly simultaneously, your car stops in between switching from reverse to first gear; exactly the same rings true as a pendulum hits its absolute low, stopping before continuing in an upward motion in either direction). Referring to the projectile's flight path depicted above, it is then gravity which causes it to move again, just like it was gravity that slowed it down and caused it to stop to begin with.
I know this wasn't supposed to be a science lecture, however if we go back to your breathing, the same exact thing happens and you can see the application: regardless of whether you are at your most calm during a great night of sleep, or you are at mile 21 of your first marathon - your breathing is rhythmic, as shown by this sine wave (ah trigonometry!). For breathing, that natural pause is most pronounced at the very end of exhalation (when the ball is at the very bottom of each dip in the path)
To put this into practice, when breathing slowly and in control, breathe out. When your exhalation is complete, hold your breath, and half a second later is when should "fire the trigger." As demonstrated in this diagram for marksmanship:
Despite the fact that most people will find that to be the most natural of breathing rhythms, there are two other variations of the breathing control method. First is the exhale-hold-exhale (meaning you hold your breath mid-exhale, take the shot, and then continue exhaling), and the other is the exact opposite of the primary method mentioned above: inhale-hold-exhale.
Some people prefer to hold their breath right in the middle of it; I personally don't recommend that one, however you might be one of those select individuals. And then some have a preference to hold their breath while they have their lungs full of air - it gives a sense of fullness that allows them to feel more stabilized. I shoot my rifle in the first method: exhale-hold-inhale. But when I am in the prone (laying on my stomach), I prefer the inhale-hold-exhale, as I feel more stabilized with my stomach and chest fully expanded. Experiment with both until you naturally discover which is best - you won't have to practice long to determine which breathing method works best for you.