Times are certainly changing, but video is probably the mot popular way that coaches and instructors break down a swing. Things like HitTrax and other launch monitors are giving objective data on batted balls, bat sensors are providing metrics on the swing and 3D motion capture is considered the gold standard for motion analysis but these things aren’t being used by the masses just yet (although I’m sure they will be in the not too distant future). And while video is a great tool, it’s important to remember that it has its limitations and things to consider. One of those things is the camera angle.
Before even looking at the swing, it’s a good idea to figure out the camera angle. Why is the angle so important? It’s because of something called parallax. Parallax is the apparent displacement of an observed object due to a change in the position of the observer. Here’s a few examples of how your angle or viewpoint can distort what you see.
The sculpture on the left is by Mattieu Robert-Ortis and the sculpture on the top right is by Troika. I’m not sure who to give credit to for the cardboard cut-out dinosaur in the lower right.
So as you can see, the angle at which you view an object is incredibly important. It’s important to remember that the actual object doesn’t change. Instead, it’s our perception of the object that changes. And while it’s best to correct for parallax by being at a 90 degree angle to the object, I’d argue that to truly understand what you’re looking at you want to observe it from all angles. Take the example by Troika on the top right. Is it a square? Or is it a circle? If we only look at it from a 90 degree angle we would see either a circle or a square (depending on which side of the sculpture we stand on). However, we gain a true understanding of the object when the camera pans from one side to the other.
Let’s take a look at a swing and how we have to consider the angle at all times. Here are two different screen shots from video of Carlos Correa (both swings are from this year).
One of the best ways to determine the angle is to look at the back line of the batters box. We know that this line is perpendicular to the line between home plate and the pitching rubber so we can use this as a guide. In the picture on the left, it looks like the shot is straight on but if you look closely at the back line, you’ll notice that we are slightly behind him. If we look at the picture on the right, it’s clear that we are a good distance in front of him.
As you can see, the change in angle makes Correa LOOK very different. Take a look at Correa’s right leg. In the picture on the left it appears to have very little bend in the knee. But if you look at the picture on the right, you can get a better idea of how much bend is occurring at the knee. Again, I think that both views have a place. It’s just important to know your angle so you can analyze everything within that context.
This is why video that has multiple angles is by far my favorite. Take a look at this Matt Carptenter clip from 2016.
It’s rare to get a shot from an MLB broadcast with so many different views but that shouldn’t stop us as coaches. Take advantage of as many views as you can. The straight ahead view is probably the most common but each view offers a slightly different perspective of the swing and its movements. You can even get creative with closeups that isolate parts of the body or swing. The more information the better as long as we understand the context or angle of the shot.
Other resources regarding parallax in baseball:
I’m certainly not the first to write about parallax errors in baseball. Driveline Baseball and Hardball Times have written about it as well. Here is the link to Driveline’s article and the Hardball Times article.
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