EOS

[Mrhart2you]

Canon 5d Mark III

[shadowsports · Accepted solution]

Welcome to the furums.  Best recommendation.  (if you must know) Send it to Canon.  

Modifying the cameras firmware or using 3rd party software can be risky and in most cases largely unreliable.  

[TCampbell]

"Officially" the only way to know the shutter count is to send the camera to Canon (e.g. for routine cleaning and maintenance) and ask them for this information.

"Unoffically" there are apps that can retrieve this information from the camera.  I use a utility (available on macOS) named "Shutter Count" (there are similar utilities for Windows users).  It is not supported by Canon, but seems to match the values that Canon would provide.

Keep in mind that while Canon offers a typical mean-time-between-failure for the shutter, occasionally cameras fail sooner -- while others last much longer.

[ebiggs1]

"...seems to match the values that Canon would provide."

And exactly where the problem lies.  If it is inaccurate for some but correct for some, you can't count on being in the correct bunch.  You will never know unless Canon confirms it. Those counters are worthless.