Focus

All cameras have both an automatic and manual focus control. Automatic can work pretty well, but professionals use manual almost all the time. Manual focus control is always the outermost ring on a video camera.

Zoom:

Nearly all video/film cameras have a zoom lens. More expensive cameras have a smoother zoom motor that makes it easier to start and stop zooming. Cheaper cameras are more abrupt. Better cameras will let you manually zoom quickly. Cheaper cameras force you to use a slow zoom motor.

Often, lenses are touted by their zoom ratio, which is a way of expressing how much a lens can magnify—that is, how telephoto it can go. While this is not insignificant, it's not terribly important either.