Strange phenomenon 5D3 + Tamron 500 SP mirror

Hello,

So the other day, I found an owl nest up on the high tree during a walk in the trail, so I thought to try my old Tamron SP 500mm F8 mirror lens with my 5D3 just for fun.
I snapped the Tamron on my 5D3 and the top LCD screen went blank, and the read LCD screen display:

"Firmware update failed.
Try updating again."

I press OK and this came up:

"Update lens firmware"
"Memory card containing firmware is required to update"

And there's nothing I can do to go pass this message...



Looks like it has something to do with the lens contacts interfacing with the camera.

Very strange!!!

By the way, this Tamron 500 F8 mirror worked fine on my 7D: I don't have AF but I do manual focus with AF indicator on when in focus. you can only adjust the speed as it has a fixed F8 aperture ( I used an Adaptall to EOS adapter )

Zigot wrote in post #15906508
Hello,

I don't have AF but I do manual focus with AF indicator on when in focus. you can only adjust the speed as it has a fixed F8 aperture ( I used an Adaptall to EOS adapter )

Sounds like you have a lens adaptor with a chip on it. I would imagine that this chip is faulty and causing the problem although I've never heard of one acting like this before.

The 5D Mk III is one of the new cameras that has the ability to update the firmware on Canon lenses that support.(like the EF 40mm 2.8 STM) Something in that AF confirm chip on your Tamron lens adapter is confusing the camera. It may not be faulty, but because it is reverse engineered, it may cause a problem that no one had thought of.

I would just tape over the contacts on the chip and that should solve your problem.

msowsun wrote in post #15907758
The 5D Mk III is one of the new cameras that has the ability to update the firmware on Canon lenses that support.(like the EF 40mm 2.8 STM) Something in that AF confirm chip on your Tamron lens adapter is confusing the camera. It may not be faulty, but because it is reverse engineered, it may cause a problem that no one had thought of.

I would just tape over the contacts on the chip and that should solve your problem.

That's awesome!!

Thank you for the suggestion of taping.