My Nikon cameras (D80 and D700) both seemingly randomly change file extension between DSC_ and RSC_. Counter does not reset. I always shoot RAW and rarely change memory card (as I import photos directly from camera to Lightroom) or any file quality related settings in the camera.
This is relatively minor issue, but ruins filename based sorting. Does anyone have any idea why that prefix changes, and is there a way to avoid that?
I know that as a workaround, Lightroom supports file renaming during import.