There was a post on what the zoom factor was about:
Also, certain cameras can come advertised with "digital" and/or "optical" zoom.
For example, I have a video camera that has 40x optical zoom and 200x digital zoom (and camera companies love to bring out the "wow!" in people).
Pressing the zoom-further button moves some mechanical "telescope-lens" to about 40 times compared to where you started. After that, a digital computer inside the camera takes over and zooms the image on-screen to about 200x the original-- analogous to as if it had Photoshop built-in it to enlarge the photos:D.
This is the reason why EGFF complains that "digital zoom" brings about poor-quality images. Digital zoom uses a computer chip (inside the camera) to zoom.
Again, the word "digital zoom" is there to bring out the "oohs" and "aahs!" in customers buying cameras -- for the manufacturers, it means more zoom.
Hope this help clear things up!