“Wrapped up like the odometer on an old car?” - the whole truth from an engineer

With the development of the secondary market for photographic equipment, customers increasingly come to my service with the question:“Is it possible Should I programmatically reset or reduce the shutter mileage before selling the camera?. Short answer: **yes, on some brands, this is possible, but it is almost impossible to hide traces of interference**.

As a specialist working with firmware software and service programs (Canon Service Tool, Nikon Service Adjustment Program), I will tell you how the frame counter protection works.

Where is the odometer physically stored?

Any digital camera has two levels of recording hours:

1. Non-volatile EEPROM/Flash memory on motherboard:camera processor records here each physical actuation of the gate circuit. This is the main hardware authority.
2. EXIF metadata block in file (JPG/RAW):When creating a snapshot, the processor takes the value from EEPROM and embeds it into the file header.

Is it possible to change the data in the EEPROM (change the mileage)?

Camera brand	Severity of memory interference	How to recognize a catch as a service engineer
Nikon	Definitely high	The mileage is hardcoded into an encrypted MakerNote array. Attempts to rewrite EEPROM service utility without replacing the gate results in a checksum error (CRC error).
Canon	Average (in artisanal services)	On some DSLRs (5D Mark III, 6D), unofficial utility programs may reset the counter. However, the physical wear and tear of the curtains and slats reveals the deception!
Sony	Very high	The ImageCount tag is encrypted with the BIONZ processor key. Changing the value blocks camera in Recovery mode.

Is it possible to simply fake the EXIF ​​file itself in Photoshop?

Some clever sellers try to edit the `ShutterCount` tag in the file before sending it to the buyer. But a trap awaits them here:MakerNote structures contain checksums and internal timestamps. If you edit just one digit, the file headers are broken.

How to check the authenticity of a file?

To be 100% confident in the seller’s honesty, demandoriginal raw RAW file (CR2, CR3, NEF, ARW, RAF)without saving through graphic editors.