...
[Zoom In/Out] allows you to enlarge or reduce the magnification of the graphic page. Select the zoom level either by selecting the zoom icons in the main menu, or by selecting [View] – [Zoom In/Out]. You may configure it this directly from the [User Definition] option. Alternatively, you can hold the ‘Ctrl’ key and scroll the mouse wheel to zoom in or out.
...
Press [OK] to apply the zoom level. Press [Cancel] to cancel the configuration.
If you zoom the page with using the ‘Ctrl’ key and scrolling mouse wheel, the magnification level will be adjusted by increments of 25% within the range of 25% to 800%.