I have a genuine Canon MR-14EX Macro Lite, and also a much cheaper generic-brand copy. They both work very nicely with my Canon EOS 650D, but the camera knows the difference; and somehow prevents the third party flash from firing in Live View mode.

Is there a solution? How does the camera know the difference? It's obviously related to the hotshoe mount/connector, but I don't know the specific details.


1 Answer 1


At a very generic level:

  • There's a small microcontroller in the flash.
  • The CPU in the camera talks to the microcontroller in the flash.
  • If the camera gets the responses it's expecting, it treats it as a Canon flash and lets you do everything with it.
  • If the camera doesn't get the responses it's expecting, it degrades the functionality.

Canon will claim this is to prevent third-party equipment from potentially damaging the camera. While this is maybe partially true, it also has the "convenient" side effect of meaning people need to buy Canon flashes...

As for exactly what the communication between the camera and the flash is, that's what the third party flash manufacturers would all like to know. It's proprietary to Canon and the only way other companies have discovered it is via reverse engineering.

(While the above may read like a rant against Canon, every other major manufacturer does the same. At least Sony are using a standard hotshoe these days, rather than a different physical connector they used a few years ago...)

  • \$\begingroup\$ +1 for 'not a rant'... & if the 3rd party ever figured out the signature, the next camera firmware update would reverse any reverse engineering the 3rd party had done... it's a fine line we tread... \$\endgroup\$
    – Tetsujin
    Commented Aug 11, 2017 at 18:40
  • 1
    \$\begingroup\$ @Tetsujin Many third parties have figured it out and have done a pretty good job of it. The game's less worth playing now since the firmware in better third-party flashes can be upgraded by the end user. \$\endgroup\$
    – Blrfl
    Commented Aug 11, 2017 at 21:13
  • \$\begingroup\$ Can you cite a reference to a reliable source? Not that I don't believe you; I'm just having a rough time trying to read up on it. Cheers. \$\endgroup\$
    – voices
    Commented Aug 12, 2017 at 20:59
  • \$\begingroup\$ Any information would be appreciated. \$\endgroup\$
    – voices
    Commented Aug 20, 2017 at 6:47

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