When using OOC JPGs (or NEFs) there should also be a "Nikon" tab in the info window, right next to EXIF. In there is a value with the number of actuations (maybe even called "shutter count", it's "Verschlussanzahl" in my German macOS, looks like a literal translation
)
But yes, it seems to be the same value as "image number", at least for the two cameras I tested.
Btw: my D7200 is already at 9475, the D3x is approaching retirement with a shutter count of currently 127778

But yes, it seems to be the same value as "image number", at least for the two cameras I tested.
Btw: my D7200 is already at 9475, the D3x is approaching retirement with a shutter count of currently 127778

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