I've bought (got for Christmas!) A Pentax 50mm 1.4f lens, but when I connect it to the body, it immediately comes up on the screen 'firmware update failed. Try updating again' 'memory card containing firmware is required to update' I put my card in my laptop and downloaded the latest update, 1.0.5 and it successfully updated BUT it still says it when I contact the lens! Won't let me do anything when it's on but as soon as my canon 18-135mm is back on the body it works perfectly... Any ideas or advice? Very new to this!
I'm surprised that nobody has answered this sooner. You cannot use a Pentax F lens on a canon camera, it just isn't compatible. You need a Canon lens or at least on that is made to work with Canon EOS cameras. The reason you get the firmware error message is that the pentax lens is shorting out the little gold contacts in the camera body.