What is "aspect ratio"?

What is "aspect ratio"?

Tim Smith (Camcorder Training Specialist) gives expert video advice on: What does the "spotlight" function on my camcorder do?; Should I use my camcorder's "widescreen" mode?; Do consumer camcorders have slow-motion capabilities? and more...

An aspect ratio really is how is the image going to lay out. Is it going to be wide or is it going to be tall? The most common is 4:3 or 16:9. 4:3 is what we've seen on television for years, but now widescreen sets are coming into popularity and they're typically 16:9 sets. So am I shooting something that's wide or am I shooting something that's more squared off, like a 4:3? You've got to decide what you're delivering it to: am I watching it on a normal TV or on a 16:9 TV? Then make the aspect ratio decision based on how you're going to watch it.