Originally posted by Skilless
So you have to hold your head perfectly still? I move around a lot when I play. Sounds like I'd end up with a neck ache...
-If you move closer to the screen does it zoom in?
There are adjustments to help keep a reasonable dead zone and still get good response when wanting to look around. There is a learning curve, and you quicly learn just how much body english you use

But with the instant feedback onscreen you quickly stop being quite so prone to excessive leaning. With the vector the learning curve is about 1/10th what it was without vector. Once you spend some time with it, you start to miss it when you forget to turn it on.
The quickest way to get comfortable with the TIR is to use it and force yourself not to turn it off for a good month assuming you play every few days. If you keep turning it off because your having trouble keeping your head still enough to aim or whatever, you will greatly extend the time you need to become 100% proficient.
Its hard for many of us to remember, but there was a time when using your thumb to look around, with an additional button for the '45º up' views was very foreign to us all and felt unnatural.