Sometimes you just want to zoom in on something. This is a nice short tutorial fortunately.
There's only three cvars to worry about:
mirv_zoom_digital
mirv_zoom_optical
Set the maximum value for both kinds of zoom. Maximum value for both is 100.
mirv_zoom_speed
The speed at which to zoom.
Use +mirv_zoom or mirv_zoom_start/mirv_zoom_stop to zoom into the maximum zoom level. It will zoom back out again when you stop zooming in.