ok this is a good one.... I just got my new camera the Canon Rebel T2i with the 18mm - 135mm lens

I have figured out autobracketing in manual mode and all good there. Don't laugh at this question but this is the first time I have had chance to work with different lenses and a camera like this.

So... I am planning on taking bracketed panos and need to be sure to lock the focus. How do I do this? especially to keep all the image in sharp focus?

For instance I have the camera lens at 18mm w F/8.0 and bracketing the shutter speed at 1/250 for normal exposure with a -2 and +2 EV

The thing I DO NOT want to happen is have the camera refocus on subjects at every 30 degree turn a rock here a tree there etc.. haha

Any tricks for this noob question? and thank you so much...