I have just recently lost the ability to change my f stop and AF with the extender connected to my equipment. The f stop, on the screen, reads 00 without the ability to adjust, while the AF just doesn't respond.
I've cleaned all contacts on 3 various compatible lenses (one f2.8 and two f4) and two camera bodies....with the same results. My method of cleaning was first; a new, clean pencil eraser....no success. Secondly, I dampened a lens cloth with alcohol, and lightly wiped the contacts....same results.
Any thoughts on my situation will be appreciated or am I just resigned to sending the 1.4x to Canon for repairs.
Thanks for any help.