How do you use optical or digital zoom on a digital camera?

Or is it done automatically or are there settings involved? I know the difference, but I don't know how to do it.

If you just hold down the zoom button, it will probably pause for a second at the end of the optical zoom range and then proceed silently into digital zoom. DON'T USE DIGITAL ZOOM THOUGH, because it really degrades the image quality. You can do a much better job of "zooming" in by cropping the image on your computer or at the photo kiosk.

Most cameras have both, and you probably have an option for using digital zoom or not - I would suggest not using digital zoom since it only makes the pixels bigger without actually magnifying the picture itself (which you can actually do with software anyway) - optical zooms, on the other hand, actually magnify the image without changing pixels...

There's a button for zooming either way. Push it towards plus and it zooms in. The other way to zoom back out. It eats up a lot of battery power, though, so use it only when you need to, and don't bother with digital zoom, as it's just in-camera cropping anyway.