how do you make the iphone 5 video camera zoom in and out?

You walk forward or backward. There is no built-in video zoom once you start filming. However, there are a number of third-party apps in the app store that provide this functionality. Do a search & read reviews.

Well that seems rather pedestrian...

BaDumPum! 😁

Thanks... I'm here all week....

Nope, you're not missing anything.