I'm trying to turn off the hud for screenshots. Everything I've read says the console command hud_info off should work, but it doesn't for me. The weird thing is, hud_crosshair off and hud_weapon off both work. I have a 60% keyboard, so don't have numpad - and +, so using those is a no-go. Anyone else run across this problem?

Try editing the User.ltx file, located in the %PUBLIC%\Documents\stalker-shoc\ folder, in order to replace the + and - keys you miss.
Locate these two lines: And change the key bindings. For instance, if you want to bind the "F3" key to zoom the cam in and the "F4" key to zoom the cam out, change the lines as these: (Beware: choose two keys that are not already assigned to other commands!)
Save the file, run the game and try to zoom the cam out in order to disable the hud.

P.S. I'm not sure, but I think you can also try issuing the "cam_zoom_out" command directly into the console.

cam_zoom_out gives me an unknown command error :(

Got a solution from this r/stalker thread: /comments/6y7av8/soc_hud_info_off_doesnt_work/
(not allowed to post links at the moment, but just add the URL fragment above to r/stalker)