Zoom does not apply to an orthographic view.
When working with a large model, the speed at which the screen is redrawn during a Zoom operation can be increased by decreasing the Motion Precision in the Preferences > Performance Options
window.
You can type the angle of view from the keyboard when the system prompts:
Enter angle of view (ABS):
The values are between 0.2 and 179. Type the angle (preceded by the letter r if you want a relative angle) and press
(Windows) or
(Mac).
The magnified window has a lower window depth so it always stays on top of normal view windows.