I have been plagued this year with the error 70 code. My r6 had the code appear throughout a wedding at the beginning of the year, after sending it away to be repaired (I think they just updated the firmware) I had it back ready to start wedding season. The next time I used it the error 70 started again, usually towards the end of the wedding day. It was sent back for repair and after a hefty repair bill of £900 to change the main board I received it back. It had been away for weeks at this point right though wedding season and I had been keen to upgrade to the R5 for a while so after losing trust with the R6 bought the R5.
First wedding with the R5, halfway through the day and error 70 starts happening on the brand new camera! It is a new SD card so this doesn't appear to be the issues, I'm now trying to eliminate what's causing it, either the adaptor? or I also use the Godox flash aswell? The most stressful part has been that I have lost photos because of this error code. Throughout the reception the error code got worse and worse and around 50 images that appeared on the back of the screen after taking them have vanished from the memory card. So the error code has also effected the images saving to the sd card. I have tried data recovery to no avail.
The repair shop mentioned that they are getting this a lot with the new mirrorless canons, what's going on? I still luckily have my second as the 5d mkiii and what a work horse that camera is, no issues many years on where as the mirrorless have been an expensive headache so far and starting to lose trust in them.
