For some reason I switched on digital lens optimization on the R1. Writing to the card took so long I thought I had broken something. Did a reset and it came back to normal but after that I realized that adding lens optimization is the culprit. Lesson learned!
It reads like he didn't know about the setting and resorted to a reset, then figured out later what caused the problem. I just hope he had saved his setting to a card and could reload them. I have a R6m2 on which you can't save the settings. It is a Royal pain with all the customization I do.
On newer Canon cameras like the R1, there are two levels of Digital Lens Optimzer corrections available: 'Standard' and 'High'. 'Standard' is enabled by default and imposes no additional speed or processing penalty. If you set DLO to 'High', however, the camera will require additional time to process images after capture.
Reminder: this setting has zero affect on RAW images: it only applies to JPEGs and controls processing in-camera. Even with it set to off, you can still apply it during RAW conversion using Canon DPP, if you like.
So, if you shoot RAW with an Adobe workflow, you can pretty much ignore this. At minimum, leave it at its default setting.
If you shoot with third-party lenses, you should disable it altogether.
