HI Tom, there's a variety of different zoom methods currently:

Mouse wheel turning
Alt + Ctrl + Left drag up and down
Ctrl + Right drag up and down
Alt + Right drag up and down
Alt+Ctrl+Middle drag - if [View] AltCtrlMMBZoom=y is set in moi.ini
Shift+Middle drag - if [View] ShiftMMBZoom=y is set in moi.ini

There is not any built in way to change using the Ctrl modifier key with one of the F1-F12 "function" keys.

But you could probably get it to work by using an external key remapping utility program, like if you're on Windows look at AutoHotkey.

- Michael

Thank you Phiro and Michael.
.
>> external key remapping<<
The reason for my question is that I had remapped the zoom-function hotkey in
a way it was ergonomically perfectly close to all the other keys I mainly use.
Now it turned out that my new keyboard has difficulties in remapping the Ctrl -
key. Maybe I can find another workaround.

When the model is zoomed out, the lines on the back will be displayed, which is disordered. What is the reason?

Hi feirui445, that's the "bleed through" display artifact. Check out here for some more information:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4987.2

- Michael

Thanks again for your time.