Works:
1) Take a weapon with a sight without magnification (e.g. ACO) or use iron sights.
2) Press and hold "Zoom temporary".
3) You are now in zoom view.
4) Press "Optics" or "Optics Temporary".
5) You are now using your sight while your view stays zoomed in.
Does not work:
1) Take a weapon with a sight without magnification (e.g. ACO) or use iron sights.
2) Press "Zoom in (toggle)".
3) You are now in zoom view.
4) Press "Optics" or "Optics Temporary".
5) You are now using your sight but the zoom is gone.