If you don't intend to make it a mod and need the one line command as mentioned above, it is the following. Type it in the ~ console.
serverconnection.chasecam(9999);
This freezes 3rd person. If you use 1st you can set up a position, then return to the frozen camera using third.
To reset make it 0. Do not make it over 10,000 or it'll crash.