Change lens protocol to support older lenses

[neo96]

Hi everyone,
is it somehow possible to influence the communication between body and lens, so that old third-party lenses would start working again?

Thanks,
neo

[ilguercio]

There's already a thread.
Short answer is NO, not yet at least.

[neo96]

Ok sorry couldn't find that one but thanks for the answer.. Hm so I have to modify the lens

[ilguercio]

Some guys in this thread probably found something useful, i don't know because it's a german forum.
Since the new 40 mm STM has received a fw update can it be looked inside for any protocol related stuff?

[neo96]

Well that's no problem for me, because I'm also german Could you give me a link?

And I think the firmware files are binary so looking inside is not a pleasure at all

[ilguercio]

http://www.dslr-forum.de/showthread.php?t=649529
I forgot to post the link.

[neo96]

Ok so according to this thread the problem is that older bodies send "18" to set the aperture, while newer bodies send "19". Some guys fixed this error by putting in a little chip which converts the "19" back into an "18".
Maybe I'll do this, too, but I'd prefer a software solution if possible.

[1%]

What does it do when you block the error? Will it still move the aperture? May be easier than hacking the chip if the lens understands to close the iris even without confirmation.

[neo96]

Blocking the error won't help since the lens doesn't understand the command to close the iris. Pressing the shutter produces an error and by pressing the "DOF-Preview-Button" just nothing happens.