pentax kx compatible problem

I`m new to dslr so please forgive the question.

Bought a Pentax ozeck 80-200mm lense from ebay. The lense fitted okay and could focus via the view finder. But the camera seems to fail to recognise the lense. It doesnt show any f numbers and fails to take a picture.

Sorry the description is so vague.

DSLR is pentax k-x
lense Pentax Ozeck 80-200mm f4.5 macro zoom lens

any help much appreciated

Does the lens have an 'A' on the aperture ring?

If it does, is it set to the 'A'?

If it doesn't, there are restrictions in the modes you can use this lens. I don't know the Kx but Check out your manual about using lens without an A setting on the aperture ring. Try manual mode and the green button.

If it doesn't have an A setting on the aperture ring (a) you have to set "allow use of aperture ring" in one of the menus (b) use it in manual mode and (c) you won't see the f/stop on the screen etc. because the camera body has no way of knowing what f/stop you have set.

Cheers, Kris.

Thanks for the replys. Camera recognises lens now. Great advice.