Thank you. I was press the button labelled AF/AE-L on the right rear. The AF/MF control on the left front, I have never previously noticed.

I primarily use my Pentax KS-1 for astrophotography so I guess my lack of knowledge on this should be no surprise. How do you disable autofocus? The AF button does not turn off autofocus in any obvious way. I am doing panoramas behind my house and plants between me and the snowcapped mountains are grabbing focus control for some pictures. I still want ISO and shutter speed automatic.