Hello John,
Some 18 month ago I tried like you to control a Canon lens and had good support from clever people working since lomg on the protocol at that time I posted here all known commands including the general structure of the protocol. Maybe you ucould search for it on the older pages.
Different to the focus motor the diaphram motor is a stepper motor that needs to be switched manually to power off, otherwise the motor will overheat an burn through. This happened to a russion guy who adapted the Canon lens to a different bajonet. The trick is to send a current stop signal after the aperture move signal and to wait inbetween for the handshake signal on the clock to disappear. The command is probably 0x0B, please look it up in my old table as I am on travel without access to my files.
The second option to command power off to the diaphram is to command it to fully open. The lens has a fully open switch and stops the motor automatically when this position is reached.
Please be aware that my project never finished and I can not prove which command is the correct one, but the physics behind are quite clear.
By the way, could you share some details about your HW and SW that you used?
Best regards
Thomas
Some 18 month ago I tried like you to control a Canon lens and had good support from clever people working since lomg on the protocol at that time I posted here all known commands including the general structure of the protocol. Maybe you ucould search for it on the older pages.
Different to the focus motor the diaphram motor is a stepper motor that needs to be switched manually to power off, otherwise the motor will overheat an burn through. This happened to a russion guy who adapted the Canon lens to a different bajonet. The trick is to send a current stop signal after the aperture move signal and to wait inbetween for the handshake signal on the clock to disappear. The command is probably 0x0B, please look it up in my old table as I am on travel without access to my files.
The second option to command power off to the diaphram is to command it to fully open. The lens has a fully open switch and stops the motor automatically when this position is reached.
Please be aware that my project never finished and I can not prove which command is the correct one, but the physics behind are quite clear.
By the way, could you share some details about your HW and SW that you used?
Best regards
Thomas