CHG_CANON wrote:
You should have your firmware updated on your digital camera as a general best practice.
But, to use an EF / EF-S lens on an EOS mirrorless body, you only need an EF-RF adapter, a piece of physical equipment.
The camera is updated. I've already done it twice. I was curious if there needed to be one particularly with the 100-400 being used on the R5. I know that one does have firmware. Thanks for your help guys.