Incorrect shutter counts in EXIF data in Canon EOS

[Rhossydd]

Whilst using Exiftool to inspect some metadata on my raw files form my Canon EOS1DsII I discovered what I hoped is a curiosity in the shutter count data.
Between two shoots the shutter accutation count jumps by about 200,000.

The only explanation I can think of is that friend borrowed the camera and loaded his own personal settings onto the camera from a SD card. I don't think there's the slightest chance he shot 200,000 frames in the two days he borrowed the camera, but I know his normal camera may well have shot that many frames in it's lifetime.
Is it possible that the shutter count from his camera has been transferred to my camera ?
Anyone heard of this before ?
Maybe more importantly, given some dealers quote the shutter count when selling used cameras and adjust the price accordingly, is there any chance of re-establishing the correct shutter count ?
One then has to ask how much you can trust this data ?

Thanks for any insights

Paul Holman

[Panopeeper]

Whilst using Exiftool to inspect some metadata on my raw files form my Canon EOS1DsII I discovered what I hoped is a curiosity in the shutter count data.
Between two shoots the shutter accutation count jumps by about 200,000

1. The shutter count is not stored in the generally accessible data (MakerNotes) of Canon cameras. Only service programs can reveal the real shutter activations.

2. The file numbering system picks up the file number from a CF card if that is greater than the number stored in the camera. When using the same card on several cameras, one should reformat the card after moving it from one camera to the other in order to continue the file numbering on that camera.

[Rhossydd]

1. The shutter count is not stored in the generally accessible data (MakerNotes) of Canon cameras. Only service programs can reveal the real shutter activations.

Interesting. Any idea what the "shutter count" field shown in Exiftool actually represents then ? Until the other card was used in the camera it seemed accurate.

2. The file numbering system picks up the file number from a CF card if that is greater than the number stored in the camera. When using the same card on several cameras, one should reformat the card after moving it from one camera to the other in order to continue the file numbering on that camera.

So will resetting the file numbering reset that "shutter count" value in EXIF ?

Thanks
Paul

[Rhossydd]

I've now reset the file numbering system for the camera, but the high "shutter count" continues to increase with each exposure in the EXIF value.

Whilst it may be correct that the true and accurate shutter count is still being held internally in the camera, where is this number being generated from and what does it represent ?

Whilst this might at first seem trivial, it may have an important consequence. Many of the pro EOSs are sold second hand quoting the number of shots taken, cameras with very high shutter counts will be marked down a lot in value. If utilities like Exiftool (and a lot of other programs use this utilitiy's functions too) report the wrong value these second hand valuations may be significantly wrong, similar to changing the recorded mileage of a car. Does this worry other people too ?

[Panopeeper]

I've now reset the file numbering system for the camera, but the high "shutter count" continues to increase with each exposure in the EXIF value

Have you tried it with a virgin CF card? I.e. format the card in computer, not in the camera.

Whilst it may be correct that the true and accurate shutter count is still being held internally in the camera, where is this number being generated from and what does it represent ?

The MakerNote (camera model specific, proprietory, unpublished) metadata contains the sequence number of the last shot. However, this is used only for generating the file names. This value is displayed by ExifTools and alike.

Whilst this might at first seem trivial, it may have an important consequence. Many of the pro EOSs are sold second hand quoting the number of shots taken, cameras with very high shutter counts will be marked down a lot in value. If utilities like Exiftool (and a lot of other programs use this utilitiy's functions too) report the wrong value these second hand valuations may be significantly wrong, similar to changing the recorded mileage of a car

One possible explanation I heard is, that this is just the intention: dealers are using brand new cameras for demo purposes and later they want to sell them as "new", so they want to have the ability to reset the counter.

[Rhossydd]

Have you tried it with a virgin CF card? I.e. format the card in computer, not in the camera.

Yes, clean fresh PC format, file renumbering reset, but still shutter count incrementing at about 200,000 more than correct.

The MakerNote (camera model specific, proprietory, unpublished) metadata contains the sequence number of the last shot. However, this is used only for generating the file names. This value is displayed by ExifTools and alike.

Looking through the detailed notes about Exiftool, the specifics of how it handles some individual makernote fields seems somewhat unclear. I still can't see what this 'shutter count' value actually is, but it's certainly incrementing on each exposure.

One possible explanation I heard is, that this is just the intention: dealers are using brand new cameras for demo purposes and later they want to sell them as "new", so they want to have the ability to reset the counter.

I've never heard this before. Whilst I can understand a reset function being there, my concern is how my count has increased so much and if there's anything I can do to correct it myself.

[Panopeeper]

Yes, clean fresh PC format, file renumbering reset, but still shutter count incrementing at about 200,000 more than correct

Take a look at this. I have not used it, but it sounds interesting; it accesses the camera tethered through the Canon SDK interface.

[Rhossydd]

Take a look at this. I have not used it, but it sounds interesting; it accesses the camera tethered through the Canon SDK interface.

Something missing here ??

What would be useful is if anyone could forward to me a set of saved settings from a 1DsII that is likely to have a shutter count below 100,000 and see if loading that changes anything.

[Rhossydd]

I've finally been sent a settings file from a lower count camera to try in my camera. The results might be of interest.

The settings file was transferred via computer onto a newly formatted SD card and loaded into my camera. The EXIF reported shutter count has now dropped to 16,000, lower than the correct figure for my camera(about 30k).

So it looks like this EXIF 'shutter count' value IS transferred with the camera's personal custom settings. It would be interesting to confirm that the true internal shutter count can't be changed.

It looks like there are two lessons to be learnt from this.

!. Don't trust any shutter count figures on an advertised camera body unless they are validated by a Canon service centre.

2. Save a custom settings file before lending an EOS1xx camera to anyone else if you want to keep the EXIF shutter count accurate.


Paul

[Mike Sellers]

Take a look at this. I have not used it, but it sounds interesting; it accesses the camera tethered through the Canon SDK interface.

Take a look at what? What do you mean? What is the SDK interface? I think my shutter count is messed up too.