Inverse Square Law
Now here I am. This is a shot taken with my iphone, but it's with a single light source. The light source between these two pictures were the same, alright? What makes them different and why? It's the same light source, it's the same camera, but why does one look like this, and one... What's the difference here? Yes?
[Woman In Audience] The light fall off?
The light fall off, okay. In simple terms, you have a dark background and you have a light background. Is that important in portraits? Yes, because sometimes you want to see the background, and other times you want a black background. So would it be important to know how to do that? And really, this is what the inverse square law is. The closer the light source is to your subject, the darker the background. See how simple that is? Closer the light source, the darker the background. So if you're in a situation, and you want a shot where it looks completely dark behind them, and you just want to feature a portrait, get that light s...
ource as close as possible. The background will be completely dark behind it, okay? Other times where you want to show the background too, pull the light source away from your subject and the background will show up. Yes?
If you were working, let's say you're working, when you say moving the light source closer and further away.
If you're working in natural light with a window, you would actually move the subject--
Move the subject.
In reference to the window.
That's correct, that's exactly what I did here.
Cool, awesome, thank you.
This picture here, literally I was about this close to the light to give me the dark background. And then I moved back about right here to get the background. So let me show an example of that in the real world instead of looking at me, which is not good. Here, she's by the door. So, she's closer to the light source because that door's creating a nice channeled light into her. And then, what I did, see how dark the background is? Now I moved her back where that back wall was, and you can see the background change in likeness, in brightness, okay? So it's a very easy example there of showing how to use the inverse square law.