Zoom works to set the focus of your "camera" and allows you to specify what it focuses it on.
orbit and zoom change the position of your camera relative to a focal point in a manner similar to the Earth orbiting the Sun but in 3 Dimensions.orbit changes your camera position with a sphere in 3 Dimensions.zoom changes the distance of your camera away from the focal point.scroll wheel to zoom in and out.Alt + Right Click will allow you to zoom by moving the mouse up or down.

X , Y, Z position of the target.