Hi bro and sis,
I am about to bid for an old Sigma 400mm f5.6 lens in EF mount (because I cannot afford a Canon 400mm f5.6L), I read in reviews that the lens will not work for new Canon bodies such as my 7D and I wouldn't mind manual focusing however, it was stated that the lens couldn't even manual focus because when attached err 99 message will come up and it will freeze on my camera.
Anyway, I know that the lens needed to be rechipped, however because that lens is pretty old and not sure how much it will cost to get Sigma to rechip it. So I am wondering could I actually just do it myself, by removing the contact on the lens and reinstall an EMF AF confirm chip that I can easily find in the ebay? Was it the same thing as rechipping the lens by Sigma? And the lens could retain all its AF capability after that, or do I have to go manual?