Media Production Mentoring

Free online film school designed with beginning filmmakers in mind.


Phi vs. Beta

Okay, I'm a total geek. I was recently researching the Phi Phenomenon because I was discussing animation, which, I believed worked because of Phi. After glancing at Wikipedia, I discovered that Phi was not what made animation work, but rather Beta Movement... both of which lead to "apparent motion"--hence the confusion.


So was I. This led to more research which led me to understand this difference between Phi and Beta:

Phi Phenomenon

Beta Movement

What's the difference?

Well, Phi is movement perceived when our brains fill in the gap with something. In a sense, our brains create an object that covers the dots. This works with any colored background or shape.

Beta, on the other hand, is movement perceived when an object changes location/shape/size/angle/etc... This is where a new dot is shown slightly ahead of the previous dot, and so it seems like the dot is moving across the screen. If I made the dots get larger, the dot would appear to be getting closer to you.

There you have it: The difference between Phi and Beta.

And, no, they aren't dormitories or fraternities at your local college. Of course, if you meet someone from such a place, you can ask them if they know the difference between the two.

~Luke Holzmann
Your Media Production Mentor


6intow said...

Amazing! I also love Wikipedia for the broad spectrum of topics available and the many interlinks to keep me busy for hours researching even something simple.

Thanks for stopping by my blog.

ajito said...

Very useful! the difference is finally almost clear for me :)
So would you say in beta movement the gap is somehow filled by our eyes and not by our brain?

Patrick Robinson said...

I think the idea, with Beta movement is that the gap is so fractional, that the apparent motion is comparable to the real movement, and in film for example, any gap there is is filled with by the motion blur, so it becomes a consistent smooth movement.