The View menu > Zoom In One Step command zooms out on the section one step. The size of the step is controlled by the Auto Zoom Step item in the Preferences form that you reach using the Options menu > Preferences command.
The default value for the Auto Zoom Step is 10 percent. What this means is that when you use the View menu > Zoom Out One Step command Section Designer decreases the magnification of all objects in the view by 10 percent.