This lets you zoom in and zoom out with out having to use the 'i' key. it will hold the zoom factor you have set.

alias zoom13 "set fov .3854; alias zoomOut zoom12; alias zoomIn zoom13"
alias zoom12 "set fov .5781; alias zoomOut zoom11; alias zoomIn zoom13"
alias zoom11 "set fov .8671; alias zoomOut zoom10; alias zoomIn zoom12"
alias zoom10 "set fov 1.3001; alias zoomOut zoom9; alias zoomIn zoom11"
alias zoom9 "set fov 1.9509; alias zoomOut zoom8; alias zoomIn zoom10"
alias zoom8 "set fov 2.9264; alias zoomOut zoom7; alias zoomIn zoom9"
alias zoom7 "set fov 4.3896; alias zoomOut zoom6; alias zoomIn zoom8"
alias zoom6 "set fov 6.5844; alias zoomOut zoom5; alias zoomIn zoom7"
alias zoom5 "set fov 9.8765; alias zoomOut zoom4; alias zoomIn zoom6"
alias zoom4 "set fov 14.8148; alias zoomOut zoom3; alias zoomIn zoom5"
alias zoom3 "set fov 22.2222; alias zoomOut zoom2; alias zoomIn zoom4"
alias zoom2 "set fov 33.3333; alias zoomOut zoom1; alias zoomIn zoom3"
alias zoom1 "set fov 50; alias zoomOut zoomMin; alias zoomIn zoom2"
alias zoomMin "set fov 75; alias zoomOut zoomMin; alias zoomIn zoom1"
alias zoomOut "zoomMin"
alias zoomIn "zoom1"

bind "+" zoomin
bind "-" zoomout
bind "*" zoommin

I use the + and - keys to zoom in/out, also the * key resets to normal.

I also put it in zoom.cfg and in vo /load zoom.cfg, that's a one time deal and if you have to redo your setup it will still be there in the cfg file.

I made this a while back:
Zathras' zoombind creator

Note that the default for "Reset zoom" is bound to Turbo in VO by default, so either pick a different zoom reset button, or put Turbo somewhere else :)