Originally posted by David82 It worked perfectly with a K-200D.
David
OK...with the 55-300 on your K-70 and the AF/MF switch turned to AF, turn the camera on. Does it say AF, AF.A, AF.S, or AF.C on the rear LCD? If not, does it have an f-number for the aperture setting on the rear LCD? Repeat with your 18-50.
If the answer to either first question is NO, the body was not able to identify that an auto-focus lens is mounted. If the answer to both questions is NO, the body was not able to determine that a lens with mount contacts is mounted. If this happens with both lenses, there might be a problem with the body. If only one of the two lenses, the problem is probably with the lens.
Even if it appears that the body may be at fault, now is a good time to take Adam's advice and clean the contacts on the body and both lenses. This is best done with a clean dry microfibre cloth and a gentle scrubbing motion on both the contacts and the mount face. The intent is to remove any soil or greasy material that may have collected on the contact surfaces. Pay particular attention to the contacts at the positions labeled "A" and "V" in the illustration below. The "A" contact is inset on the body side, making it a little more difficult.
It is the "A" contact that tells the body that a lens with contacts is mounted and the "V" contact that identifies it as an AF lens.
Steve