While the canvas is still in zoom mode, instant zoom is enabled
by default. Instant zoom allows zooming in at the point of left mouse
clicking by a factor of 1/2, i.e. the region centered at the point
of left clicking will be magnified by a factor or 2. Also, the Zoom
Focus Time in the time display panel will be updated with the time
where left clicking on the canvas is detected. In the process, the
cursor remains zoom-plus cursor. Shift-click, on the
other hand, will do the opposite. While holding down Shift key, the
cursor will be changed to a zoom-minus cursor as in Figure
to indicate zooming out is the action associated with left clicking.
The zoom factor is 2 in this case.