[chefjohn]

Hi, novice at best. When I press button half way down it does attempt to focus but the two red arrows appear. While this lens work with my camera on auto focus? How do I know if its the camera or lens or neither. Recent pawn shop purchase. I live outside Peoria IL. area. The only 35mm non digital in all the shops. this lens does have a green Macro setting on it besides the white 28-50.

[Adam]

If your lens looks like this, then yes, it should be able to AF:
Takumar-F 28-80mm F3.5-4.5 Reviews - Non-SMC Pentax Zoom Lenses - Pentax Lens Reviews & Lens Database

[ChipB]

Hi, assuming the lens is, in fact, an AF lens (the one Adam lists) there's a couple of things you can do to verify that the lens 'should' auto-focus.

First, will the lens manually focus from infinity to close? Try it off the camera.

Second, on the lens mount, there is a round thing that appears to be a screw-driver slot - this is the AF link point between the lens and the camera body. Try turning it with a screw-driver - does the lens change focus?

If all that checks out, does the camera auto-focus with a different lens? If so, try cleaning the contacts on the lens and see if that makes a difference. If not, or you don't have another lens to test with, try fresh batteries.

Good luck!!

[chefjohn]

thanks, yes that is the lens, i will try the suggestions