I just purchased a C645-EOS so I can use my Contax 645 lenses on my Blackmagic Pocket Cinema 6K Pro. It will not allow me to stop the lens down and it's not activating the auto focus. Is there a Firmware update? I have used many [Canon /Sigma] lenses with the BMPCC 6kPro and never had a problem, I know the Contax lenses lenses Are good because they work perfectly on my Contax 645.