Look a bit to the left (ie, with compass out, face body north and head to 310 degrees). Try to zoom your vision. To do this, weirdly, you don't move your head in the direction it's facing, but instead must slide it sideways towards 90 degrees.
This is mirrored on the right hand side.
Edit:
It's most obvious if you look backwards over your shoulder in-game, and try to use TrackIR to zoom. You have to move your head backwards to zoom in, which feels weird.