Digital zoom vs. optical zoom
When you use the digital zoom:
The quality of the image gets lower. What you see is pixelated and less clear.
The quality of the recording does not change.
The zoom level of the recording does not change.
When you use the optical zoom (only for cameras that support optical zoom):
The quality of the image that you see does not change.
The quality of the recording does not change.
If you use the optical zoom on your camera while recording, the zoom levels used will be reflected in your recording.