HP Photosmart 730 series - Manual (Page 29)

Chapter 2: Taking pictures and recording video clips 29
To turn digital zoom off and return to optical zoom, press the
Zoom Out button until digital zooming stops. Release the
button, and then press the button again.
NOTE Digital zoom reduces the resolution of an image, so
your picture will tend to be more pixilated than the same
image taken with an optical zoom. If you just intend to
e-mail an image or post it to a website, this loss of
resolution will not be noticeable, but in situations where
the highest quality counts (such as printing), skip the
digital zoom and use the cropping tools in your image
editing software to zero in on your subject.