Optical zoom is accomplished by changing the focal length of the lens.
It is the preferred method of zooming, as it does not degrade the image quality.
Digital zoom is much like taking a big picture and cutting (crop) a rectangle out of the middle, then increasing that rectangle in size to equal the size of the original big picture. You then have a big picture made up of less pixels.
The middle now looks closer but it is degraded.
Most cameras will let you turn-off digital zoom.
It is wise to do so.
If necessary, you can always do a digital zoom later with software.
It is called cropping.
by my question it will be painfully obvious I know very little about cameras. what is the difference between the optical zoom and the digital zoom. and which one is more important? thanks