I bought the Pentax K-S2. In first use with an SMC Pentax-FA 80-320 mm 1:4.5-5.6 lens, I wanted to use AF mode, but this not available in the camera menus. When I enter the menu, in AF settings, the active area AF isn’t available. And I can’t change MF to AF in the info settings. Could you give me a solution to this? Or tell me why it does not work?
The manual for the Pentax K-S2 shows the location of the focus mode switch on page 8 and describes its operation on page 54.
Make sure the focus mode switch is set to autofocus.
Make sure the lens is capable of autofocus. The SMC Pentax FA interchangable lens manual indicates that it is.
If there is a problem caused by malfunction then either the camera or the lens could be the source. Testing the lens with another camera and the camera with another lens should narrow it down in that case.